English band importance functions in competing speech for Spanish-speaking second-language learners of English.

Band importance functions (BIFs) for speech perception have been well characterized for native speakers of English tested with English speech-in-noise materials. Fewer datasets are available for speech-in-speech recognition or for listeners who are second-language learners of English. The present study evaluated BIFs for sentences in a two-talker speech background for Spanish/English bilinguals who were second-language (L2) learners of English and two groups of native (L1) English speakers. The target speech was monaural, with three target talkers presented in separate blocks of trials. The L2 speakers and one group of L1 speakers were tested with a diotic masker (MoTm); a second group of L1 speakers was tested with a monaural masker (MmTm). The L2 speakers had higher speech reception thresholds compared to L1 speakers tested with the same stimuli (MoTm), but more similar performance compared to L1 speakers tested in the more challenging condition (MmTm), which lacked binaural difference cues. Compared to both L1 groups, L2 speakers had shallower psychometric functions and benefited less from semantic context. The BIFs differed for the three talkers, but they were similar for all three groups of participants, indicating that L1 and L2 speakers largely relied on the same spectral cues for speech-in-speech recognition.