Second-language learning in adolescents with cochlear implants

Speech signals delivered via cochlear implants (CIs) lack spectro-temporal details, yet, young-implanted children can develop good native language skills (L1). This study explores three research questions: 1. Can adolescents with CIs learn a second language (L2)? 2. Is there a difference in spoken (auditory-A) vs. written (visual-V) L2 skills? 3. Which perceptual and cognitive factors influence L2 learning? Two groups (L1 = Dutch, age 12—17 years), one with normal hearing (NH) and one with CIs, and both learning English (L2) at school, participated. L1 and L2 proficiency was measured in receptive vocabulary (A), comprehension (A, V), and general proficiency (V). Further, basic auditory functioning, in temporal (gap detection) and spectral (spectral ripple detection) resolution, and cognitive functioning, in IQ, working memory, and attention, were measured. Preliminary data (n = 7 per group) indicated comparable L1 proficiency between NH and CI groups. While some CI users showed L2 proficiency within the NH range, on average, L2 proficiency was lower for the CI group. This effect was more pronounced for auditory tests. Reduced temporal and spectral resolution, but no difference in cognitive tests, were observed in CI group compared to NH, emphasizing the importance of auditory factors in L2 learning.