How much does language proficiency by non-native listeners influence speech audiometric tests in noise?

Abstract

Objective: The current study investigates the extent to which the linguistic complexity of three commonly employed speech recognition tests and second language proficiency influence speech recognition thresholds (SRTs) in noise in non-native listeners. Design: SRTs were measured for non-natives and natives using three German speech recognition tests: the digit triplet test (DTT), the Oldenburg sentence test (OLSA), and the Göttingen sentence test (GÖSA). Study sample: Sixty-four non-native and eight native listeners participated. Results: Non-natives can show native-like SRTs in noise only for the linguistically easy speech material (DTT). Furthermore, the limitation of phonemic-acoustical cues in digit triplets affects speech recognition to the same extent in non-natives and natives. For more complex and less familiar speech materials, non-natives, ranging from basic to advanced proficiency in German, require on average 3-dB better signal-to-noise ratio for the OLSA and 6-dB for the GÖSA to obtain 50% speech recognition compared to native listeners. Conclusions: In clinical audiology, SRT measurements with a closed-set speech test (i.e. DTT for screening or OLSA test for clinical purposes) should be used with non-native listeners rather than open-set speech tests (such as the GÖSA or HINT), especially if a closed-set version in the patient's own native language is available.

Key Words::

• Non-natives
• speech recognition in noise
• digit triplet test
• sentence test in noise
• linguistic complexity

Acknowledgements

This work was supported by the Ministry of Science and Culture of Lower Saxony, Germany, and the EFRE funded project ‘Network for multilingual hearing and speech intelligibility diagnostics’ (HurDig), and by Deutsche Forschungsgemeinschaft (KO 942-13, EXC 1077 Hearing4all). We thank Rebecca Carroll and Melanie Zokoll for their valuable contribution to this project, and students who took part in the measurements. Three anonymous reviewers are gratefully acknowledged for helping to improve the manuscript. The copyright of the German Matrix Sentence Tests (OLSA) audio material is owned by the non-profit organization HörTech gGmbH (owned in majority by the Universität Oldenburg). The test is available as a medical product for modern audiometers of different brands. For research purposes, sample sentences and free trial versions of the research version of the software are available from www.hoertech.de.

Declaration of interest: The authors report no conflicts of interest.