Can family language policy predict linguistic, socio-emotional and cognitive child and family outcomes? A systematic review

Figures & data

Figure 1. Search query.

Figure 2. PRSIMA flow diagram.

Table 1. Overview of selected studies, describing method, age of focal child(ren), languages, country, outcome variables and related FLP component(s).

Study	Method	(Mean) Age focal children	Languages and country	Outcome(s)	Related FLP component(s)
Altman et al. (2014)	Child and parental interview, linguistic assessment/tasks 65 children	4;6–6;9 yo	Russian & Hebrew Israel	L: language use and proficiency	B, P, M ^(*FLP studied as a whole)
Cheung et al. (2018)	Parental questionnaire, linguistic assessment/task, recording/observation, teacher interview 92 children	49.87 mo	Cantonese & English USA	L: proficiency C	P, M
Curdt-Christiansen (2016)	Recording/observation over six months, FLP audit, parental interview 3 focal children (3 families)	5–7 yo	Mandarin/Hokkien & English Malay & English Tamil & English Singapore	L: language use, proficiency, language shift S-E: linguistic and general well-being	B, P (beliefs shape P)
Danjo (2018)	Recording/observation, parental and child interview, teacher interview, parental diary entries over 16 months 2 children (1 family)	4 & 6 yo	Japanese & English UK	L: language use, proficiency S-E: general well-being C	P
De Houwer (2007)	Parental questionnaire 1899 families	6–10 yo	Several HLs & Dutch Belgium	L: language use	P
Dekeyser and Agirdag (2018)	Child questionnaire 500 children	10–12 yo	Arabic and/or Berber & Dutch Turkish & Dutch Eastern European languages & Dutch + other HLs Belgium	L: emotional language use S-E: emotional language use ^(*domains overlap)	B, P
Dekeyser and Stevens (2019)	Child questionnaire 312 children	10–12 yo	Arabic and/or Berber & Dutch + other HLs Belgium	L: proficiency	B, P, M
Dolson (1985)	Child questionnaire, teacher reports, standardised test scores 108 children	10–12 yo	Spanish & English USA	L: proficiency S-E: general well-being C	P
Doyle (2018)	Parental interview, parental questionnaire 5 children (4 families)	4;8–11;2 yo	Hebrew & Estonian Slovenian & Estonian Swedish & Estonian Turkish & Estonian Estonia	L: language use, proficiency S-E: linguistic and general well-being	P, M
Duarte et al. (2014)	Parental and child interview, parental questionnaire, linguistic assessment/task 133 children	11 yo	Russian & German Turkish & German Vietnamese & German Germany	L: writing proficiency in German and HL C	P
Eisenchlas et al. (2019)	Parental questionnaire, parental interview 6 mothers of 8 children in total	5–10 yo	Taiwanese & English ^(*during the sojourning, Taiwanese becomes the IL) Australia	L: proficiency S-E: linguistic and general well-being ‘other’: developing self-reflection	M
Han, Lee, and Waldfogel (2012)	Parental interview, linguistic assessment/task over five years 6800 children	from birth to 5 yo	Several HLs & English USA	L: proficiency C	P
Hoff et al. (2018)	Parental questionnaire, linguistic assessment/task over thirty months 178 children (139 children from Spanish-speaking or bilingual homes)	from 30 mo to 60 mo	Spanish & English USA	L: proficiency	P
Howard et al. (2014)	Parental questionnaire, recording/observation, linguistic assessment/task, teacher interview, school records 447 children	5, 8 yo & 10 yo	Spanish & English USA	L: proficiency C	P
Ibrahim et al. (2013)	Parental questionnaire, linguistic assessment/task 49 children ^(*28 native speakers of Arabic, 21 children with L1 Hebrew, their L2 Arabic was confined to the school context)	8–10 yo	Arabic & Hebrew Israel	L: proficiency C	P, M
Juan-Garau and Pérez-Vidal (2001)	Recording/observation, parental diary entries over approx. three years 1 child	from 1;3–4;2 yo	English & Catalan Spain	L: degree of bilingualism, rate of CS	P, M
Kasuya (1998)	Recording/observation, parental reports over approx. 15 months 4 children	2;10–4;1 yo	Japanese & English USA	L: language use/choice	P, M
Kuo (1974)	Parental questionnaire, parental interviews, parental and researcher evaluations, observations, linguistic assessment/task 47 children (44 families)	30–72 mo	Chinese & English USA	L: proficiency, degree of bilingualism	B, P, M
Lewis et al. (2016)	Parental questionnaire, linguistic assessment/task 93 children	43–66 mo	Spanish & English USA	L: proficiency	P, M
Li (2006)	Recording/observation, parental interview, teacher interview, document collection 3 focal children	6–7 yo	Mandarin and/or Cantonese & English Canada	L: language use, proficiency, maintenance, degree of bi-/trilingualism and biliteracy C	B, P, M
Li and Tan (2016)	Parental questionnaire, linguistic assessment/task 76 children	66.8 mo	Chinese & English Singapore	L: proficiency C	P, M
Lü and Koda (2011)	Parental questionnaire, linguistic assessment/task 37 children	7–8 yo	Chinese & English USA	L: proficiency C	P
Makarova, Terekhova, and Mousavi (2019)	Parental questionnaire, linguistic assessment/task 30 children	5–7 yo	Russian & English + additional HLs Canada	L: proficiency	B, P
Mattheoudakis, Chatzidaki, and Maligkoudi (2017)	Parental questionnaire 202 parents	9–10 yo	Albanian & Greek Greece	L: language use, proficiency C	P, M
Miękisz et al. (2017)	Parental questionnaire, linguistic assessment/task 53 bilingual and 53 monolingual (English) children	24–36 mo	Polish & English UK, Ireland	L: proficiency	B, P
Mishina-Mori (2011)	Recording/observation over approx. one year 2 children	from 2;3–3;2yo & from 2;5–3;3 yo	Japanese & English USA	L: language use/choice, degree of bilingualism, rate of CS	P, M
O’Toole et al. (2017)	Parental questionnaire, linguistic assessment/task 250 children	24–36 mo	Maltese & English Polish & English English & Hebrew English & Irish Portuguese & French Turkish & German UK, Israel, Ireland, France, Germany	L: proficiency C	P
Palacios, Kibler, and Simpson Baird (2017)	Parental interview, linguistic assessment/task 77 children	2–5 yo	Spanish & English USA	L: proficiency	P
Pham and Tipton (2018)	Parental questionnaire, linguistic assessment/task 69 children	5;6–8;6 yo	Vietnamese & English USA	L: proficiency	P
Quay (2012)	Parental questionnaire, parental interview, linguistic assessment/task, recording/observation, parental diary entries, day-care diaries, day-care interview over approx. 10 months 2 children	from 1 to 1;10 yo & from 1;1–2;4 yo	English & Chinese & Japanese English & German & Japanese Japan	L: degree of trilingualism	P, M
Rinker, Budde-Spengler, and Sachse (2017)	Parental questionnaire, linguistic assessment/task 19 children	24–36 mo	Turkish & German Germany	L: proficiency	P
Scarpino et al. (2019)	Parental questionnaire, productive vocabulary and sound tasks 199 children	3–6;6 yo	Spanish & English USA	L: proficiency	P
Schwartz (2008)	Parental and child questionnaire, linguistic assessment/task 70 children	6;11–7;5	Russian & Hebrew Israel	L: proficiency, language maintenance	B, P, M
Slavkov (2017)	Parental questionnaire 170 children	8;8 yo	French (official minority language) & English (official majority language) & several HLs (minority) Canada	L: degree of bi-/multilingualism, multilingualism vs bilingualism	B, P, M
Slavkov (2015)	Recording/observation, parental diary entries over approx. 2;2 years 1 child	from 0;1–2;3 yo	Bulgarian & English Canada	L: proficiency, language attrition/shift and reactivation, degree of bilingualism	P, M
Smith-Christmas (2017)	Recording/observation 1 child	8 yo	Gaelic & English ^(*Gaelic only in school context) UK (Scotland)	L: language use, proficiency S-E: general well-being	B, P
Tsai et al. (2012)	Parental questionnaire, linguistic assessment/task 79 children	4–7 yo	Chinese (Mandarin, Cantonese, or Taiwanese) & English USA	L: proficiency	P
Van Mensel and Yao (2017)	Parental interview, recording/observation over 6 months 2 children (1 family)	2;4 & 4;9 yo	(focus on) Mandarin Chinese & Dutch Belgium	L: degree of bilingualism	P, M
Van Mensel (2018)	Recording/observation over almost 2 years (fam 1) and 6 months (family 2) 5 children (2 families)	2–6 yo	Spanish & Dutch Mandarin & Dutch (+sometimes English) Belgium	L: familylect* S-E: general well-being ^(*we view familylect both as a language practice and a linguistic outcome, due to the ongoing, dynamic process)	B, P
Verhagen, Mulder, and Leseman (2017)	Parental questionnaire, linguistic assessment/task, cognitive task 200 bilingual and 829 monolingual children	3 yo	Turkish & Dutch Arabic and/or Berber & Dutch Netherlands	C	P
Yeh, Ho, and Chen (2015)	Child questionnaire 234 children	7–12 yo	Vietnamese & Taiwanese Taiwan	Combination of L and S-E (or ‘other’): child attitudes towards and motivation for learning the minority language	P
Yoshimitsu (2000)	Parental and child questionnaire, parental and child interview, linguistic assessment/task, recording/observation 10 children	10–11 yo	Japanese & English Australia	L: proficiency, language maintenance	B, P, M

Table 2. Overview of selected studies with outcomes in the linguistic sphere

Outcome	Study	Outcome: additional info/ focus on	Component	Component: additional info
Language proficiency	Altman et al. (2014)	Child self-reported HL & IL proficiency (speaking), actual proficiency	B-P-M	FLP studied as a whole (strict pro-HL, mild pro-HL and pro-bilingual policy) Strictness of pro-HL FLP and openness to bilingual FLP Greater influence of peers and siblings than parents
	Cheung et al. (2018)	HL & IL vocabulary knowledge	P-M	Familial HL & IL use in specific activities (dinner, reading out loud, playing with family), sibling’s HL & IL use/input
	Curdt-Christiansen (2016)	MT & English	B-P	Lower MT (mother tongue) input due to caregivers/Family members’ negative attitudes towards MT and societal pressure to be proficient in English
	Danjo (2018)	HL	P	Parental language use (OPOL & especially self-isolation of HL speaking mother and children from IL during everyday language learning opportunities)
	Dekeyser and Stevens (2019)	Child self-reported HL & IL proficiency	B-P-M	All components as perceived by child HL proficiency: parental attitudes towards HL (children’s own attitudes towards IL or HL have no effect), parental HL use (at least one parent), mother’s HL proficiency, number of non-IL languages spoken in the house (possibly due to implicit importance placed on multilingualism), language brokering by child (= management) Child’s view of school policy also matters IL proficiency: siblings’ IL use, mother’s IL proficiency, language brokering by child
	Dolson (1985)	Bilingual and HL proficiency, HL reading proficiency	P	HL use as main home language (seems to be an intervening factor, rather than an independent variable)
	Doyle (2018)	HL	P-M	Language use/exposure (HL use in parent-dyad as well as in the parent-child-dyad), reading bedtime stories
	Duarte et al. (2014)	IL & HL writing proficiency	P	Exposure: quantity and quality of familial HL & IL input ! effects of familial quantitative IL input decrease when controlled for duration of IL contact and the type of school children attend
	Eisenchlas et al. (2019)	HL (becomes IL during sojourning)	M	Sojourning
	Hoff et al. (2012)	productive IL skills	P	Familial IL use, parental IL proficiency
	Hoff et al. (2018)	HL & IL	P	HL & IL exposure ! faster child IL acquisition, given the same levels of IL & HL exposure at home
	Howard et al. (2014)	IL reading comprehension	P	Home and school IL exposure
	Ibrahim et al. (2013)	HL & IL reading speed and accuracy	P-M	(explicit choice for) Home and school HL & IL exposure, school choice
	Kuo (1974)	HL & IL	B-P-M	parental attitudes, relative language use, language use between parents and between parent and child, story reading (IL was not impeded by exposure) ! significant effect of child’s age on IL proficiency
	Lewis et al. (2016)	HL & IL expressive vocabulary and oral comprehension	P-M	HL exposure, mother-child book reading, child IL use, frequency of (engaging child in) storytelling
	Li (2006)	HL & IL speaking, reading and writing skills	B-P-M	Parental attitudes towards IL & HL, parental perceptions of their minority status in the host society, parental proficiency in IL & HL, management efforts such as HL school attendance and HL teaching at home
	Li and Tan (2016)	MT oral and written abilities	P-M	Children’s MT (mother tongue) literacy related activities (either independently or with parents), child language preference
	Lü and Koda (2011)	HL language and literacy skills, especially oral vocabulary knowledge	P	Familial HL use/exposure
	Makarova, Terekhova, and Mousavi (2019)	HL	B-P	parental attitudes and familial language use/exposure
	Mattheoudakis, Chatzidaki, and Maligkoudi (2017)	HL comprehension, reading and writing	P-M	Exposure at home and via HL classes, parental HL promotion (likely to stem from positive parental attitudes towards HL)
	Miękisz et al. (2017)	HL & IL vocabulary size	B-P	children’s frequency of HL & IL use (HL & IL vocabulary), parental concern about language or rather sensitivity to limited vocabulary (HL vocabulary), limited maternal HL & IL use (limited HL vocabulary), siblings’ IL language use (IL vocabulary), maternal education level
	O’Toole et al. (2017)	HL & IL vocabulary size, TCV & TV	P	Quantity and quality of familial HL & HL exposure, mixing, parental proficiency (e.g. parental IL use relates negatively to Total Conceptual Vocabulary (TCV) & Total Vocabulary (TV), possibly because of limited parental IL proficiency or more mixed input) Parental concerns about language development, parental education status, and child age might also play a role.
	Palacios, Kibler, and Simpson Baird (2017)	IL vocabulary	P	Maternal IL input (might be connected with maternal IL proficiency) Child care also seems to play a role: children staying at home in parental care have lower HL & IL vocabulary scores, possibly due to less engagement in early vocabulary building activities
	Pham and Tipton (2018)	HL & IL receptive and productive vocabulary	P	Cumulative HL & IL exposure, quantity and quality of parental HL input, HL activities, several child-internal factors IL proficiency was only related to child-internal factors (age, phonological memory)
	Rinker, Budde-Spengler, and Sachse (2017)	HL productive vocabulary	P	Quantity and quantity of familial HL exposure (the word category did play a role: related to home/family context or not)
	Scarpino et al. (2019)	phonological abilities: phonological whole-word proximity	P	Maternal (especially for IL outcomes) and child (especially for HL outcomes) HL & IL use in mother-child-dyads
	Schwartz (2008)	HL	B-P-M	Children’s attitudes (towards development of both languages at home & HL literacy acquisition), parental permission of HL & IL co-existence, HL literacy practices/efforts, support of HL-literacy schools
	Slavkov (2015)	HL language acquisition	P-M	Exposure (OPOL at home, 10-day trip to Bulgaria), explicit parental strategies to establish monolingual HL context
	Smith-Christmas (2017)	Gaelic (minority language used in school context)	B-P	Parental attitudes (e.g. de-normatising Gaelic use by child, framing Gaelic as school language), familial and school input (no/barely any Gaelic at home, only at school)
	Tsai et al. (2012)	HL expressive and receptive proficiency	P	Parental HL use (possibly steered by parental cultural orientation)
	Yoshimitsu (2000)	HL	B-P-M	child language use, child initiatives to learn HL, child attitudes towards reading HL books, parental management efforts (e.g. Saturday schooling, HL activities at home, use of a Japanese network in Australia)
Language use	Altman et al. (2014)	HL & IL	B-P-M	FLP studied as a whole (strict pro-HL, mild pro-HL and pro-bilingual policy) Strictness of pro-HL FLP and openness to bilingual FLP Greater influence of peers and siblings than parents, but no matter the FLP: more HL use to parents, more IL to siblings
	Curdt-Christiansen (2016)	Parental and child MT use	B-P	Family members’ disparate attitudes towards MT (mother tongue) influences language use of the different family members
	Danjo (2018)	HL	P	Parental language use (OPOL & especially self-isolation of HL speaking mother and children from IL during everyday language learning opportunities)
	De Houwer (2007)	HL & IL	P	Parental language input (patterns)
	Dekeyser and Agirdag (2018)	emotional language use	B-P	Primary language of communication with siblings, both parents or the father (if IL, more likely to prefer IL in negative emotion situations), child attitudes towards HL acquisition
	Doyle (2018)	HL	P-M	Language use/exposure (HL use in parent-dyad as well as in the parent-child-dyad, mixing in parent-child-dyads), reading bedtime stories
	Kasuya (1998)	HL	P-M	Parental discourse strategies and consistency
	Li (2006)	HL & IL	B-P-M	Parental attitudes towards IL & HL, parental perceptions of their minority status in the host society, parental proficiency in IL & HL, management efforts such as HL school attendance and HL teaching at home
	Mattheoudakis, Chatzidaki, and Maligkoudi (2017)	HL	P-M	Exposure at home and via HL classes, parental HL promotion (likely to stem from positive parental attitudes towards HL)
	Mishina-Mori (2011)	Child HL use, CS and mixing	P-M	Parental language use, discourse strategies and reaction to child language use, CS or mixing
	Smith-Christmas (2017)		B-P	Parental attitudes (e.g. de-normatising Gaelic use by child, framing Gaelic as school language), familial and school input (no/barely any Gaelic at home, only at school), subtle parental critiquing of child Gaelic proficiency
Language shift or maintenance	Curdt-Christiansen (2016)	shift	B–P	Lower MT (mother tongue) input due to caregivers/Family members’ attitudes towards MT & English, and societal pressure to be proficient in English
	Li (2006)	maintenance	B-P-M	Parental attitudes towards IL & HL, parental perceptions of their minority status in the host society, parental proficiency in IL & HL, management efforts such as HL school attendance and HL teaching at home
	Schwartz (2008)	maintenance	B-P-M	Children’s attitudes (towards development of both languages at home & HL literacy acquisition), parental permission of HL & IL co-existence, HL literacy practices/efforts, support of HL-literacy schools
	Slavkov (2015)	attrition/shift and reactivation	P-M	Exposure (OPOL at home, 10-day trip to Bulgaria), explicit parental strategies to establish monolingual HL context, IL day-care
	Yoshimitsu (2000)	maintenance	B-P-M	child language use, child initiatives to learn HL, child attitudes towards reading HL books, parental management efforts (e.g. Saturday schooling, HL activities at home, use of a Japanese network in Australia)
Degree of bi/multilingualism	Juan-Garau and Pérez-Vidal (2001)	Active bilingualism	P-M	Parental discourse strategies, use of monolingual puppets, trip to UK
	Kuo (1974)	Balance	B-P-M	Parental attitudes, relative language use, language use between parents and between parent and child, story reading (IL was not impeded by exposure) ! significant effect of child’s age on IL proficiency
	Li (2006)	Balance of bi-/trilingualism and biliteracy	B-P-M	Parental attitudes towards IL & HL, parental perceptions of their minority status in the host society, parental proficiency in IL & HL, management efforts such as HL school attendance and HL teaching at home
	Mishina-Mori (2011)	Active bilingualism	P-M	Parental language use, discourse strategies and reaction to child language use, CS or mixing
	Quay (2012)	Active trilingualism	P-M	Parental language use and discourse strategies
	Slavkov (2017)	Active bi-/multilingualism + number of languages child knows	B-P-M	School choice (possible indicator of positive attitudes to multilingualism), language of schooling, HL school attendance, parental language use in parent-dyads and parent-child-dyads, child language use with siblings, parental HL literacy commitments
	Slavkov (2015)	Active bilingualism	P-M	Exposure (OPOL at home, 10-day trip to Bulgaria), explicit parental strategies to establish monolingual HL context
	Van Mensel and Yao (2017)	Active bilingualism	P-M	Exposure, parental language use and discourse strategies
Rate of CS	Juan-Garau and Pérez-Vidal (2001)		P-M	Parental language use, discourse strategies, use of monolingual puppets, trip to UK
	Mishina-Mori (2011)		P-M	Parental language use, discourse strategies and reaction to child language use, CS or mixing
Other	Van Mensel (2018)	familylect	B-P	Ideologies regarding speech correctness or normativity, attitudes towards language separation and codemixing, familial language use
	Yeh, Ho, and Chen (2015)	child attitudes towards and motivation to learn HL	P	Parental HL use at home, living with (HL speaking) immigrant parent(s)

Table 3. Overview of selected studies with outcomes in the socio-emotional sphere.

Outcome	Study	Outcome: additional info/ focus on	Component	Component: additional info
Linguistic well-being	Curdt-Christiansen (2016)	Frustration, regret	B-P	Conflicting attitudes towards MT between family members, societal pressure to be proficient in English, incongruent parental ideologies and practices (e.g. regret for not providing enough MT input), and incongruent everyday practices and parental expectations/impact belief
	Doyle (2018)	Lamentation of parents, child’s reluctance to speak HL	P-M	Language use/exposure (HL use in parent-dyad as well as in the parent-child-dyad), reading bedtime stories, child HL proficiency
	Eisenchlas et al. (2019)	Child impatience and frustration	M	limited proficiency > conflict with classmates, impatient and frustrated behaviour
General well-being	Curdt-Christiansen (2016)	Social tensions	B-P	Conflicting attitudes towards MT between family members, societal pressure to be proficient in English
	Danjo (2018)	Family relations (bonding and unbonding), perception of identity and culture, HL parent feeling left out	P	Parental language use (OPOL & self-isolation of HL speaking mother and children from IL during everyday language learning opportunities), conflicting parental and child language use, mother and maternal language practices as embodiment for HL, Japan and Japanese culture (sometimes used by children in socio-emotional context: using HL to comfort mother, using IL to challenge mother …), child IL preference/frequent language use
	Dolson (1985)	Psycho-social adjustment and interaction at school	P	HL use as main home language (seems to be an intervening factor, rather than an independent variable)
	Doyle (2018)	Parents feeling left out, ‘migrant’-feeling, being perceived as ‘weird’ for being bilingual/bicultural, identity	P-M	Language use in parent-dyad and in the parent-child-dyad, child HL proficiency, parental proficiency
	Eisenchlas et al. (2019)	Identity formation, mother-child bonding, bonding with family overseas, confidence, motivation, rebellion/resistance, conflict with classmates	M	Sojourning, child proficiency
	Smith-Christmas (2017)	Possibly family relations and self-worth child	B-P	Parental attitudes (e.g. de-normatising Gaelic use by child, framing Gaelic as school language), familial and school input (no/barely any Gaelic at home, only at school), subtle parental critiquing of child Gaelic proficiency
	Van Mensel (2018)	Emotional bond and family ties	P	Familylect
Other	Dekeyser and Agirdag (2018)	Emotional language use	B-P	Primary language of communication with siblings, both parents or the father (if IL, more likely to prefer IL in negative emotion situations), child attitudes towards HL acquisition
	Yeh, Ho, and Chen (2015)	Child attitudes towards and motivation for learning the minority language	P	Parental HL use at home, living with (HL speaking) immigrant parent(s)

Cognitive outcomes.

Table 4. Overview of selected studies with outcomes in the cognitive sphere.

Study	Outcome: additional info/ focus on	Component	Component: additional info
Cheung et al. (2018)	Conceptual knowledge	P	Familial HL & IL use in specific activities (dinner, reading out loud, playing with family), sibling’s HL & IL use/input
Danjo (2018)	Linguistic creativity (e.g. grammatically or phonologically adapting ‘loan words’ from one language into the other)	P	Parental language use (OPOL & self-isolation of HL speaking mother and children from IL during everyday language learning opportunities)
Dolson (1985)	Literacy, academic grade point average (also: being held back, mathematics, effort grade point average)	P	HL use as main home language (seems to be an intervening factor, rather than an independent variable)
Duarte et al. (2014)	Written language abilities IL and HL	P	Exposure: quantity and quality of familial HL & IL input ! effects of familial quantitative IL input decrease when controlled for duration of IL contact and the type of school children attend
Han, Lee, and Waldfogel (2012)	School readiness, early reading and math skills	P	Familial IL use, parental IL proficiency, SES
Howard et al. (2014)	English word reading skills	P	Home and school IL exposure
Ibrahim et al. (2013)	Reading speed and accuracy	P-M	(explicit choice for) Home and school HL & IL exposure
Li (2006)	Literacy skills	B-P-M	Parental attitudes towards IL & HL, parental perceptions of their minority status in the host society, parental proficiency in IL & HL, especially management efforts such as HL school attendance and HL teaching at home
Li and Tan (2016)	Written language abilities	P-M	Children’s MT (mother tongue) literacy related activities (either independently or with parents), child language preference
Lü and Koda (2011)	HL language and literacy skills, especially oral vocabulary knowledge	P	Familial HL use/exposure
Mattheoudakis, Chatzidaki, and Maligkoudi (2017)	HL reading and writing skills	P-M	Exposure at home and via HL classes, parental HL promotion (likely to stem from positive parental attitudes towards HL)
O’Toole et al. (2017)	Total Conceptual Vocabulary (TCV)	P	Quantity and quality of familial HL & HL exposure, mixing, parental proficiency (e.g. parental IL use relates negatively to Total Conceptual Vocabulary (TCV), possibly because of limited parental IL proficiency or more mixed input) Parental concerns about language development, parental education status, and child age might also play a role.
Verhagen, Mulder, and Leseman (2017)	Inhibitory control, self-control	P	Exposure to multiple home languages, parental language use

Table 5. Extensive overview of methods used per age group.

Age group	Method	Study	Extensive information
0–3 years old	Recordings and/or observations	Mishina-Mori (2011)	Observations, audio- and video-recordings (parent-child-dyads), over approx. one year
		Quay (2012)	Weekly video-recordings at home and in day-care of interactions (caregiver(s)-child)
		Slavkov (2015)	Recordings of spontaneous parent-child interactions during a 10-day trip
	Parental interview	Quay (2012)	n.s.
	Parental diary entries	Quay (2012)	Diary on child’s language production
		Slavkov (2015)	Diary on child’s emotional, cognitive, motor and language development
	Linguistic assessments or tasks	Miękisz et al. (2017)	Productive vocabulary assessment: CDI (IL & HL)
		O’Toole et al. (2017)	Productive and receptive vocabulary assessment: CDI (IL & HL)
		Quay (2012)	MCDI (IL & HL)
		Rinker, Budde-Spengler, and Sachse (2017)	Vocabulary assessment: ELAN, TIGE, TILDA
		Verhagen, Mulder, and Leseman (2017)	PPVT (IL)
	Parental questionnaire	Miękisz et al. (2017)	Polish version of PaBiQ-IT
		O’Toole et al. (2017)	PaBiQ-IT
		Quay (2012)	n.s.
		Rinker, Budde-Spengler, and Sachse (2017)	German adaptation of PaBiQ
		Verhagen, Mulder, and Leseman (2017)	Daily Communication Questionnaire (frequency of language and literacy activities with children)
	Other	Verhagen, Mulder, and Leseman (2017)	Several cognitive tasks: inhibitory control (Stroop), visuospatial working memory (Six Boxes task), selective attention (visual search task), and delay of gratification (Gift Delay task & Gift-in-bag task)
		Quay (2012)	Day-care diaries, interview day-care staff
Overlap 0–6	Recordings and/or observations	Hoff et al. (2018)	Recordings of children’s spontaneous speech
		Juan-Garau and Pérez-Vidal (2001)	Audio- and video-recordings of family interactions (parent(s)-child) + notes over 3 years
		Kasuya (1998)	Recorded speech samples, observations of family interactions between HL speaking parent and child, over approx. 15 months
		Kuo (1974)	Observation of language use in family
		Van Mensel and Yao (2017)	Recordings of family interactions (one-on-one parent-child conversations and conversations with multiple interlocutors, with special attention for dinner time conversations, recorded by mother)
		Van Mensel (2018)	Observations and recording of family interactions (parent(s)-child(ren))
	Parental interview	Han, Lee, and Waldfogel (2012)	Early Childhood Longitudinal Study-Birth Cohort data: parental interviews, over five years
		Kuo (1974)	Focus on child language development and parental feelings/attitudes toward the language patterns of their child
		Palacios, Kibler, and Simpson Baird (2017)	Focus on language use of family members in interaction with the child and vice versa and childcare (Early Childhood Longitudinal Study – Kindergarten Class)
		Van Mensel and Yao (2017)	Semi-structured interview on perspective information on FLP
	Parental diary entries	Juan-Garau and Pérez-Vidal (2001)	Notes and parental diary keeping on language development, over approx. three years
	Linguistic assessments or tasks	Han, Lee, and Waldfogel (2012)	Early Childhood Longitudinal Study-Birth Cohort data: productive and receptive language tasks (e.g. Letter recognition, phonological awareness, sight word recognition, PreLAS subset, etc.), over five years
		Hoff et al. (2018)	EOWPVT (IL & HL) + recordings of spontaneous speech over thirty months + CDI
		Kuo (1974)	Receptive vocabulary: PPVT English and Chinese
		Lewis et al. (2016)	Picture Vocabulary and Oral Comprehension (Batería III Woodcock-Muñoz) and Woodcock-Johnson III Tests of Achievement (IL & HL)
		Palacios, Kibler, and Simpson Baird (2017)	Woodcock-Muñoz language survey (IL & HL)
		Scarpino et al. (2019)	Woodcock-Muñoz Language Survey-Revised + Bilingual Phonological Assessment (BiPA) (IL & HL)
	Parental questionnaire	Hoff et al. (2018)	Home Language Environment Questionnaire in interview-form
		Kuo (1974)	n.s.
		Lewis et al. (2016)	Home activities questionnaire
		Scarpino et al. (2019)	64-item background and language survey
	Other	Kasuya (1998)	Parental reports on parental language use and child language development, over approx. 15 months – not specified whether these reports were obtained via an interview
		Kuo (1974)	Independent parental and researcher evaluations of child’s relative language abilities, rating child’s bilingual balance
4–6 years old	Recordings and/or observations	Cheung et al. (2018)	Classroom observations (to assess amount of IL & HL used by teachers)
		Danjo (2018)	Observation and audio-recording of family interactions (parent-child and between siblings) over 16 months + classroom observations (children’s verbal interactions)
	Parental and child interview	Altman et al. (2014)	Parent: background child and parent, child language acquisition, FLP (practices, management and attitudes parents) Child: FLP (e.g. reported language choice with parents and siblings, language use at home, frequency of CS) and self-rated language abilities (IL & HL)
		Danjo (2018)	Semi-Structured parental interviews (focus on perception of practices and beliefs) and ethnographic parental and child interviews as part of daily conversations and during playtime (+ teacher interviews)
	Parental diary entries	Danjo (2018)	Parental diary entries and email exchanges with the researcher
	Linguistic assessments or tasks	Altman et al. (2014)	Adapted noun-verb picture naming, non-word repetition and complex syntax in sentence repetition – (IL & HL)
		Cheung et al. (2018)	Picture identification and picture naming tasks (IL & HL) – developed based on MCDI and CCDI-C
		Li and Tan (2016)	Picture description task (oral language ability), Chinese character recognition task (HL)
	Parental questionnaire	Cheung et al. (2018)	(linguistic) background/demographic information, IL-HL use by each family member, IL-HL use during home activities
		Li and Tan (2016)	Home language and literacy environment questionnaire: demographic information, SES, children’s language preference at home, parents’ and children’s Chinese language and literacy activities
	Other	Cheung et al. (2018)	Teacher interviews
		Danjo (2018)	Teacher interviews
Overlap 4–12	Recordings and/or observations	Curdt-Christiansen (2016)	Observation and recording of family interactions (adult family members-child-siblings) over six months
		Howard et al. (2014)	Classroom observations
		Li (2006)	Direct and participant home and school observations: focus on literacy activities, child language use and choice in different settings, interactional patterns with teachers and peers, use of or talk about home literacy experiences
	Parental interview	Curdt-Christiansen (2016)	Formal and informal interviews, focus on parental ideologies towards bilingual policy and perceived evaluation of different languages in Singapore
		Doyle (2018)	Semi-structured interview on FLP, (parental) language competences, challenges …
		Eisenchlas et al. (2019)	Semi-structured interview on background, family history, FLP, reflection on and evaluation of sojourning experience
		Li (2006)	Informal conversations with parents + semi-structured interview: children’s home literacy, parental beliefs and values of language learning, perceptions of schooling in Canada
	Linguistic assessments or tasks	Howard et al. (2014)	Subset of Woodcock Language Proficiency Battery-Revised (IL & HL): Picture Vocabulary, Letter-Word Identification, Passage Comprehension
		Makarova, Terekhova, and Mousavi (2019)	Russian language speech samples via picture description task (HL)
		Pham and Tipton (2018)	Picture naming and picture identification task (IL & HL)
		Schwartz (2008)	Composite measure of Russian receptive and productive lexical knowledge using semantic categories knowledge, antonym knowledge, word description, PPVT-R (HL)
		Tsai et al. (2012)	Language Assessment Scales – Oral (Pre-LAS version) and PPVT-III (IL & HL)
	Parental questionnaire	De Houwer (2007)	Place of residence, family members age and citizenship, language(s) spoken at home by parents and children
		Doyle (2018)	Demographic information
		Eisenchlas et al. (2019)	Online survey on parental ideologies, language practices, HL management and demographic family information
		Howard et al. (2014)	Demographic survey on school and family (SES, home language and literacy practices, children’s schooling history …) – sometimes administered in interview-form, sometimes with follow-up calls
		Makarova, Terekhova, and Mousavi (2019)	Demographic background, parental knowledge of IL, HL and other languages, parental language attitudes, parental and child language use within and outside of the family, child’s exposure to language …
		Pham and Tipton (2018)	(via telephone) selected items from Bilingual Input Output Survey and Alberta Language Environment Questionnaire
		Tsai et al. (2012)	Vancouver Index of Acculturation, Parental Cultural Maintenance Scale, Language Use and Preference Questionnaire
	Parental and child questionnaire	Schwartz (2008)	Parents: based on existing survey, including demographic and background information, parental language practices, management, ideologies and opinion of importance of children’s knowledge of different languages Children: specifically developed, including demographic and background information, children’s language management, practice and ideologies
	Other	Curdt-Christiansen (2016)	FLP audit
		Howard et al. (2014)	Teacher interviews and school records
		Li (2006)	Teacher semi-structured interviews + collection of children’s written work
7–12 years old	Recordings and/or observations	Smith-Christmas (2017)	Recordings and observations of natural family interactions between adult family members and child
		Yoshimitsu (2000)	Recording of naturally occurring family conversations (parent-child) and participant observation
	Parental and child interview	Duarte et al. (2014)	computer-assisted interviews Children: language use, social networks, cultural identity and acculturation attitudes Parents: family language use (language use between parents, between parents and children and between siblings), education and socio-economic status of the family, cultural capital (=number of books in the house), migration background, child’s time living in Germany and school type
		Yoshimitsu (2000)	Demographic background, schooling, IL & HL proficiency, language choice and use, initiative in studying HL …
	Linguistic assessments or tasks	Duarte et al. (2014)	Children: written narrative task (∼förmig-Tulpenbeet), digit span memory task (IL & HL) Parents: vocabulary test (CFT 20-R) (IL & HL)
		Ibrahim et al. (2013)	Reading tasks: word and text reading (IL & HL)
		Lü and Koda (2011)	PPVT-Revised, Auditory Discrimination Test, Deletion tasks (adaptation i.a. from CTOPP), Woodcock Reading Mastery Tests-Revised (IL & HL)
			Nonverbal intelligence via Raven’s Standard Progressive Matrices (control variable)
		Yoshimitsu (2000)	Reading large numerals, counting objects, naming objects, describing facial expressions, IL mixing, level of speech, flow of discourse, coherence in discourse
	Parental questionnaire	Duarte et al. (2014)	Written survey on personal language use, personal social networks, cultural identity, acculturation attitudes, migration status …
		Ibrahim et al. (2013)	Background and child language practices at home (incl. language(s) for reading, writing, TV and computer games)
		Lü and Koda (2011)	Survey on home language and literacy support (HL use at home, HL exposure, home literacy environment, parents’ and children’s engagement in literacy practices)
		Mattheoudakis, Chatzidaki, and Maligkoudi (2017)	Survey on demographic information, parents’ language ability and use, child’s knowledge and use of different languages, child’s IL & HL acquisition and development, parental efforts for IL & HL development, potential difficulties with child’s language development.
		Slavkov (2017)	Demographic information, FLP (e.g. parental and child language practices), school language choice + qualitative, open-ended questions on parents’ satisfaction with the choice of language of schooling for their children
	Child questionnaire	Dekeyser and Agirdag (2018)	Online survey including children’s emotional language use, children’s and parents’ language practices, proficiency, attitudes and background characteristics
		Dekeyser and Stevens (2019)	Online survey including proficiency, language practices and attitudes of children and their family members, family relations, socioeconomic and sociocultural settings, demographic background, children’s well-being, ethnic identification and family relationships
		Dolson (1985)	Home Language Use Survey
		Yeh, Ho, and Chen (2015)	Self-developed survey on family socio-demographic profile, children’s and their family’s attitudes about learning HL, school support for HL
	Parental and child questionnaire	Yoshimitsu (2000)	Demographic background, schooling, IL & HL proficiency, language choice and use, initiative in studying HL …
	Other	Dolson (1985)	Teacher reports (home language, school information, SES …), standardised test scores in English reading, mathematics, and Spanish reading vocabulary, academic point average, Student Oral Language Observation Matrix …
		Li (2006)	Teacher semi-structured interviews + collection of children’s written work

Altman, C., Z. Burstein Feldman, D. Yitzhaki, S. Armon Lotem, J. Walters, Z. Burstein-Feldman, and J. Walters. 2014. “Family Language Policies, Reported Language use and Proficiency in Russian - Hebrew Bilingual Children in Israel.” Journal of Multilingual and Multicultural Development 35 (3): 216–234. doi:10.1080/01434632.2013.852561.

 Web of Science ®Google Scholar

Cheung, S., P. F. Kan, E. L. L. I. E. Winicour, and J. Yang. 2018. “Effects of Home Language Input on the Vocabulary Knowledge of Sequential Bilingual Children.” Bilingualism. doi:10.1017/S1366728918000810.

 Web of Science ®Google Scholar

Curdt-Christiansen, X. L. 2016. “Conflicting Language Ideologies and Contradictory Language Practices in Singaporean Multilingual Families.” Journal of Multilingual and Multicultural Development 37 (7): 694–709. doi:10.1080/01434632.2015.1127926.

 Web of Science ®Google Scholar

Danjo, C. 2018. “Making Sense of Family Language Policy: Japanese-English Bilingual Children’s Creative and Strategic Translingual Practices.” International Journal of Bilingual Education and Bilingualism 0 (0): 1–13. doi:10.1080/13670050.2018.1460302.

 Web of Science ®Google Scholar

De Houwer, A. 2007. “Parental Language Input Patterns and Children’s Bilingual use.” Applied Psycholinguistics 28 (3): 411–424. doi:10.1017/S0142716407070221.

 Web of Science ®Google Scholar

Dekeyser, G., and O. Agirdag. 2018. “Determinants of Emotional Language use Preferences of Ethnolinguistic Minority Children in Antwerp, Belgium.” International Journal of Bilingual Education and Bilingualism 0 (0): 1–17. doi:10.1080/13670050.2018.1523866.

 Web of Science ®Google Scholar

Dekeyser, G., and G. Stevens. 2019. “Maintaining one Language While Learning Another: Moroccan Children in Belgium.” Journal of Multilingual and Multicultural Development 40 (2): 148–163. doi:10.1080/01434632.2018.1493115.

 Web of Science ®Google Scholar

Dolson, D. P. 1985. “The Effects of Spanish Home Language use on the Scholastic Performance of Hispanic Pupils.” Journal of Multilingual and Multicultural Development 6 (2): 135–155. doi:10.1080/01434632.1985.9994192.

 Google Scholar

Doyle, C. 2018. “‘She’s the big dog who Knows’-Power and the Father’s Role in Minority Language Transmission in Four Transnational Families in Tallinn.” Philologia Estonica Tallinnensis 3: 17–43. doi:10.22601/PET.2018.03.01.

 Google Scholar

Duarte, J., I. Gogolin, T. Klinger, and B. Schnoor. 2014. “Mehrsprachige Kompetenzen in Abhängigkeit von Familialen Sprachpraxen.” Lili - Zeitschrift Fur Literaturwissenschaft Und Linguistik 44 (174): 66–85. doi:10.1007/bf03379517.

 Google Scholar

Eisenchlas, S. A., A. C. Schalley, G. Y. Qi, and P. S. Tsai. 2019. “Home and Away – Implications of Short-Term Sojourning of Young Australian Bilinguals.” Lingua. International Review of General Linguistics. Revue internationale De Linguistique Generale (2018), doi:10.1016/j.lingua.2019.02.007.

 Web of Science ®Google Scholar

Han, W. J., R. H. Lee, and J. Waldfogel. 2012. “School Readiness among Children of Immigrants in the US: Evidence from a Large National Birth Cohort Study.” Children and Youth Services Review 34 (4): 771–782. doi:10.1016/j.childyouth.2012.01.001.

 PubMed Web of Science ®Google Scholar

Hoff, E., D. Giguere, J. Quinn, and J. Lauro. 2018. “The Development of English and Spanish Among Children in Immigrant Families in the United States.” Pensamiento Educativo. Revista de Investigación Educacional Latinoamericana 55 (2): 1–17.

 PubMedGoogle Scholar

Howard, E. R., M. M. Páez, D. L. August, C. D. Barr, D. Kenyon, and V. Malabonga. 2014. “The Importance of SES, Home and School Language and Literacy Practices, and Oral Vocabulary in Bilingual Children’s English Reading Development.” Bilingual Research Journal 37 (2): 120–141. doi:10.1080/15235882.2014.934485.

 Google Scholar

Ibrahim, R., M. Schwartz, J. Kahn-Horwitz, and M. Leikin. 2013. “Bi-cultural Aspects of Second Language Learning in a Bilingual Context.” Asian EFL Journal 15 (4): 65–89.

 Google Scholar

Juan-Garau, M., and C. Pérez-Vidal. 2001. “Mixing and Pragmatic Parental Strategies in Early Bilingual Acquisition.” Journal of Child Language 28 (1): 59–86. doi:10.1017/S0305000900004591.

 PubMed Web of Science ®Google Scholar

Kasuya, H. 1998. “Determinants of Language Choice in Bilingual Children: The Role of Input.” International Journal of Bilingualism 2 (3): 327–346. doi:10.1177/136700699800200304.

 Google Scholar

Kuo, E. C. Y. 1974. “The Family and Bilingual Socialization: A Socioling-Uistic Study of a Sample of Chinese Children in the United States.” Journal of Social Psychology 92 (2): 181–191. doi:10.1080/00224545.1974.9923096.

 Web of Science ®Google Scholar

Lewis, K., L. E. Sandilos, C. S. Hammer, B. E. Sawyer, and L. I. Méndez. 2016. “Relations Among the Home Language and Literacy Environment and Children’s Language Abilities: A Study of Head Start Dual Language Learners and Their Mothers.” Early Education and Development 27 (4): 478–494.

 PubMed Web of Science ®Google Scholar

Li, G. 2006. “Biliteracy and Trilingual Practices in the Home Context: Case Studies of Chinese-Canadian Children.” Journal of Early Childhood Literacy 6 (3): 355–381. doi:10.1177/1468798406069797.

 Google Scholar

Li, L., and C. L. Tan. 2016. “Home Literacy Environment and its Influence on Singaporean Children’s Chinese Oral and Written Language Abilities.” Early Childhood Education Journal 44 (4): 381–387. doi:10.1007/s10643-015-0723-4.

 Web of Science ®Google Scholar

Lü, C., and K. Koda. 2011. “Impact of Home Language and Literacy Support on English-Chinese Biliteracy Acquisition among Chinese Heritage Language Learners.” Heritage Language Journal 8 (2): 44–80.

 Google Scholar

Makarova, V., N. Terekhova, and A. Mousavi. 2019. “Children’s Language Exposure and Parental Language Attitudes in Russian-as-a-Heritage-Language Acquisition by Bilingual and Multilingual Children in Canada.” International Journal of Bilingualism 23 (2): 457–485. doi:10.1177/1367006917740058.

 Web of Science ®Google Scholar

Mattheoudakis, M., A. Chatzidaki, and C. Maligkoudi. 2017. “Heritage Language Classes and Bilingual Competence: The Case of Albanian Immigrant Children in Greece.” International Journal of Bilingual Education and Bilingualism 0 (0): 1–17. doi:10.1080/13670050.2017.1384447.

 Web of Science ®Google Scholar

Miękisz, A., E. Haman, M. Łuniewska, K. Kuś, C. O’Toole, and N. Katsos. 2017. “The Impact of a First-Generation Immigrant Environment on the Heritage Language: Productive Vocabularies of Polish Toddlers Living in the UK and Ireland.” International Journal of Bilingual Education and Bilingualism 20 (2): 183–200. doi:10.1080/13670050.2016.1179259.

 Web of Science ®Google Scholar

Mishina-Mori, S. 2011. “A Longitudinal Analysis of Language Choice in Bilingual Children: The Role of Parental Input and Interaction.” Journal of Pragmatics 43 (13): 3122–3138. doi:10.1016/j.pragma.2011.03.016.

 Web of Science ®Google Scholar

O’Toole, Ciara, Daniela Gatt, Tina M. Hickey, Aneta Miękisz, Ewa Haman, Sharon Armon-Lotem, Tanja Rinker, Odelya Ohana, Christophe dos Santos, and Sophie Kern. 2017. “Parent Report of Early Lexical Production in Bilingual Children: A Cross-Linguistic CDI Comparison.” International Journal of Bilingual Education and Bilingualism 20 (2): 124–145. doi:10.1080/13670050.2016.1179258.

 Web of Science ®Google Scholar

Palacios, N., A. K. Kibler, and A. Simpson Baird. 2017. “Childcare, Language-use, and Vocabulary of Second-Generation Latino Immigrant Children Growing up in a new Immigrant Enclave in the United States.” Early Child Development and Care 187 (3–4): 690–706.

 Web of Science ®Google Scholar

Pham, G., and T. Tipton. 2018. “Internal and External Factors That Support Children’s Minority First Language and English.” Language, Speech, and Hearing Services in Schools 49 (3): 595–606. doi:10.1044/2018_LSHSS-17-0086.

 PubMed Web of Science ®Google Scholar

Quay, S. 2012. “Discourse Practices of Trilingual Mothers: Effects on Minority Home Language Development in Japan.” International Journal of Bilingual Education and Bilingualism 15 (4): 435–453. doi:10.1080/13670050.2012.665828.

 Web of Science ®Google Scholar

Rinker, T., N. Budde-Spengler, and S. Sachse. 2017. “The Relationship between First Language (L1) and Second Language (L2) Lexical Development in Young Turkish-German Children.” International Journal of Bilingual Education and Bilingualism 20 (2): 218–233.

 Web of Science ®Google Scholar

Scarpino, S. E., C. S. Hammer, B. Goldstein, B. L. Rodriguez, and L. M. Lopez. 2019. “Effects of Home Language, Oral Language Skills, and Cross-Linguistic Phonological Abilities on Whole-Word Proximity in Spanish-English–Speaking Children.” American Journal of Speech-Language Pathology 28 (1): 174–187.

 PubMed Web of Science ®Google Scholar

Schwartz, M. 2008. “Exploring the Relationship between Family Language Policy and Heritage Language Knowledge among Second Generation Russian-Jewish Immigrants in Israel.” Journal of Multilingual and Multicultural Development 29 (5): 400–418. doi:10.1080/01434630802147916.

 Web of Science ®Google Scholar

Slavkov, N. 2017. “Family Language Policy and School Language Choice: Pathways to Bilingualism and Multilingualism in a Canadian Context.” International Journal of Multilingualism 14 (4): 378–400. doi:10.1080/14790718.2016.1229319.

 Web of Science ®Google Scholar

Slavkov, N. 2015. “Language Attrition and Reactivation in the Context of Bilingual First Language Acquisition.” International Journal of Bilingual Education and Bilingualism 18 (6): 715–734. doi:10.1080/13670050.2014.941785.

 Web of Science ®Google Scholar

Smith-Christmas, C. 2017. “‘Is it Really for Talking?’: The Implications of Associating a Minority Language with the School.” Language, Culture and Curriculum 30 (1): 32–47. doi:10.1080/07908318.2016.1230619.

 Web of Science ®Google Scholar

Tsai, K. M., H. Park, L. L. Liu, and A. S. Lau. 2012. “Distinct Pathways from Parental Cultural Orientation to Young Children’s Bilingual Development.” Journal of Applied Developmental Psychology 33 (5): 219–226.

 Web of Science ®Google Scholar

Van Mensel, L., and L.-H. Yao. 2017. “‘Ni yao Shenme? Patatje?’ Gezinstaalbeleid en Meertalige Praktijken in een Chinees Migrantengezin.” Tijdschrift Voor Nederlandse Taal- En Letterkunde 3 (133): 4–5.

 Google Scholar

Van Mensel, L. 2018. “‘Quiere Koffie?’ The Multilingual Familylect of Transcultural Families.” International Journal of Multilingualism 15 (3): 233–248. doi:10.1080/14790718.2018.1477096.

 Web of Science ®Google Scholar

Verhagen, J., H. Mulder, and P. P. M. Leseman. 2017. “Effects of Home Language Environment on Inhibitory Control in Bilingual Three-Year-old Children.” Bilingualism: Language and Cognition 20 (1): 114–127. doi:10.1017/S1366728915000590.

 Web of Science ®Google Scholar

Yeh, Y. C., H. J. Ho, and M. C. Chen. 2015. “Learning Vietnamese as a Heritage Language in Taiwan.” Journal of Multilingual and Multicultural Development 36 (3): 255–265. doi:10.1080/01434632.1995.9994593 To.

 Web of Science ®Google Scholar

Yoshimitsu, K. 2000. “Japanese School Children in Melbourne and Their Language Maintenance Efforts.” Journal of Asian Pacific Communication 10 (2): 255–278. doi:10.1075/japc.10.2.07yos.

 Google Scholar

Hoff, E., C. Core, S. Place, R. Rumiche, M. Señor, and M. Parra. 2012. “Dual Language Exposure and Early Bilingual Development.” Journal of Child Language 39 (1): 1–27. doi:10.1017/S0305000910000759.

 PubMed Web of Science ®Google Scholar