Monolingual and Bilingual Word Recognition and Word Learning in Background Noise.

The participants were healthy university students with normal hearing and no reported speech or attention problems, so the findings do not show what happens in people with hearing loss, speech disorders, or attention problems. Experiment 1 tested adults aged 18 to 24, and Experiment 2 tested adults aged 18 to 33, so the findings do not cover children or older adults. The experiments used separate groups of participants, not the same people in both tasks, so small unmeasured differences between groups could contribute to the pattern. IQ was not directly measured; the researchers treated the groups as similar because they were students from the same universities. Experiment 2 reaction-time analysis used only correct trials, had few observations, and excluded eight participants, so those results should be read cautiously. Experiment 2 used a −2 dB noise level, and the task was very difficult, so it may not have been sensitive enough to detect a bilingual advantage or disadvantage.

Do not conclude that bilingualism causes a general speech-in-noise difficulty. The bilingual group was less accurate only for familiar word recognition in the −8 dB noise condition, and bilinguals learned new words in noise as well as monolinguals. The study also used healthy young adults with normal hearing.