Second language speech comprehension in noise: A hazard to aviation safety

Simple Norwegian and English sentences were read by a bilingual adult, tape recorded and presented individually to bilingual adults with English or Norwegian as their first language and good command of the other. Each 65 dB sentence was first presented in so strong background USASI noise (75dB) that it could not be perceived, and was repeated with the noise level progressively reduced in 2 dB steps from presentation to presentation until the sentence was adequately repeated by the subject. The results demonstrated that for both groups the first (native) language sentences were correctly repeated after fewer presentations, that is at a lower signal-to-noise ratio, than the second language sentences. The difference between the first (native) language comprehension threshold and the second language comprehension threshold was statistically significant for both the Norwegian and the English subject groups.