Inflectional morphology in German hearing-impaired children

Abstract

Despite modern hearing aids, children with hearing impairment often have only restricted access to spoken language input during the ‘critical’ years for language acquisition. Specifically, a sensorineural hearing impairment affects the perception of voiceless coronal consonants which realize verbal affixes in German. The aim of this study is to explore if German hearing-impaired children have problems in producing and/or acquiring inflectional suffixes expressed by such phonemes. The findings of two experiments (an elicitation task and a picture-naming task) conducted with a group of hearing-impaired monolingual German children (age 3–4 years) demonstrate that difficulties in perceiving specific phonemes relate to the avoidance of these same sounds in speech production independent of the grammatical function these phonemes have.

Key words::

• Coronal obstruents
• inflectional suffixes
• language acquisition
• morphology
• nasals
• phoneme production
• phoneme reception
• sensorineural hearing impairment
• syllable structure
• verbal agreement

Notes

Declaration of interest: The research reported in this paper was supported by a German research foundation (DFG) grant (project number: RO923/1-1, HE 2869/6-1). For the authors no conflicts of interest are declared.

Supplementary material available online

Supplementary Appendix A and B.

Notes

1. A reviewer of this paper suggested that the difficulties in discriminating the phonemes /s/ and /t/ in the above-mentioned FinKon discrimination task might also be due to a closer acoustic distance between the two phones [s] and [t] as opposed to the nasal [n]. A recently proposed metric of phonetic similarity by Mielke (12) provides, however, no empirical evidence for the claim that the obstruents [s] and [t] are considerably closer with respect to acoustic distance than [s] versus [n] or [t] versus [n]. Given this metric, it seems unlikely that the results observed in the FinKon discrimination test could be due to differences in the acoustic distance between the critical speech sounds. As the reviewer comments, Mielke's findings do not preclude that with respect to perceptual confusions between the three critical consonants [s], [t], and [n] the last-mentioned consonant might be less confusable in perception than the two first-mentioned consonants even in adult subjects with unimpaired hearing. To our knowledge, however, no such evidence is available for German.

2. We adopt here an analysis of German syllable structure by Grijzenhout (16) who proposes that the nucleus is bipositional and may be occupied by a long vowel, or a short vowel plus a sonorant (i.e. a glide, a liquid, or a nasal). Segments in the nucleus may be followed by a less sonorant consonant in the coda position of a rhyme. Obstruents never occupy a nucleus position but the coda or appendix position.

3. A reviewer of this paper suggested that the observed differences of HI children in producing the word final obstruents /s/ and /t/, on the one hand, and nasals, on the other hand, might be related to differences in the acquisition of these phonemes. Whereas nasals are among the earliest sounds in babies’ inventories, especially /s/ is one of the last speech sounds to be acquired by German children (30). Hence, the avoidance of /s/ and /t/ might be related to the fact that the HI children have not acquired these sounds yet. Two points argue against this suggestion, however. Firstly, all of the tested HI children were well able to produce the phonemes /s/ and /t/ in word final position. Secondly, although the phoneme /s/ is acquired relatively late by German children, difficulties in acquiring this phoneme relate to its place of articulation, with many children producing an interdental [θ] instead of the alveolar [s]. Since this pronunciation is very common among German children well into school age (30 p. 62–5), we judged such productions of the phoneme /s/ as correct. Note also, that [θ] and [s] are similar in pitch and require perception of a similar frequency range according to the speech banana.