Intelligibility of native and non-native Dutch speech

Abstract

The intelligibility of speech is known to be lower if the speaker is non-native instead of native for the given language. This study is aimed at quantifying the overall degradation due to limitations of non-native speakers of Dutch, specifically of Dutch-speaking Americans who have lived in the Netherlands 1–3 years. Experiments were focused on phoneme intelligibility and sentence intelligibility, using additive noise as a means of degrading the intelligibility of speech utterances for test purposes. The overall difference in sentence intelligibility between native Dutch speakers and American speakers of Dutch, using native Dutch listeners, was found to correspond to a difference in speech-to-noise ratio (SNR) of approximately 3 dB. The main segmental contribution to the degradation of speech intelligibility by introducing non-native speakers and/or listeners is the confusion of vowels, especially those that do not occur in American English. Vowels that are difficult for second-language speakers to produce are also difficult for second-language listeners to classify; such vowels attract false recognition, reducing the overall recognition rate for all vowels.