English phoneme and word recognition by nonnative English speakers as a function of spectral resolution and English experience

Previous studies have shown that nonnative listeners have poorer speech recognition compared to native listeners, particularly under difficult listening conditions. While native English speaking listeners can tolerate large amounts of distortion to speech, listeners to whom English is a second language (L2) may require a much longer period of learning to develop equally robust central speech patterns.; The present study looked at speech perception by nonnative listeners under conditions of noise (SNR of l5dB, 10dB, 5dB, 0dB) and reduced spectral information (2, 4, 6, 8 and 16 frequency bands). Subjects were tested using speech processed to simulate the listening condition typically encountered by cochlear implant listeners. Normal hearing listeners whose first language was Spanish were tested with American English phonemes, words and sentences. Results were compared with results for native English listeners tested under the same conditions.; Speech perception depends on phonetic, lexical and linguistic knowledge. We wanted to determine the relative contributions of phonemic and lexical processing to speech recognition as a function of language experience by varying both the spectral resolution and the linguistic complexity of the materials. Contrary to what was initially expected, results determined that the main difficulty nonnative listeners encountered in L2 perception is in vowel perception, not in linguistic integration. Context factors were determined using the Boothroyd and Nittrouer model (1988), in which a parameter ‘k’ reflects the degree of predictability in the sentence material. Results suggest that early L2 learners are able to use linguistic information when they are forced to do so.; Plomp's SRT (Speech Reception Threshold) model (1986) was applied to the data. Plomp defines a parameter ‘D’ that measures the distortion in perception of the speech stimuli. The difficulties in speech perception of the L2 by nonnative listeners are similar to difficulties encountered by cochlear implant patients. We do not suggest that lack of experience with a L2 is the same as suffering from a hearing loss or hearing impairment, but results show that this simple model can account for both factors.