The perception of speech modulation cues in lexical tones is guided by early language-specific experience

Abstract

A number of studies showed that infants reorganize their perception of speech sounds according to their native language categories during their first year of life. Still, information is lacking about the contribution of basic auditory mechanisms to this process. This study aimed to evaluate when native language experience starts to noticeably affect the perceptual processing of basic acoustic cues [i.e., frequency-modulation (FM) and amplitude-modulation information] known to be crucial for speech perception in adults. The discrimination of a lexical-tone contrast (rising versus low) was assessed in 6- and 10-month-old infants learning either French or Mandarin using a visual habituation paradigm. The lexical tones were presented in two conditions designed to either keep intact or to severely degrade the FM and fine spectral cues needed to accurately perceive voice-pitch trajectory. A third condition was designed to assess the discrimination of the same voice-pitch trajectories using click trains containing only the FM cues related to the fundamental-frequency (F0) in French- and Mandarin-learning 10-month-old infants. Results showed that the younger infants of both language groups and the Mandarin-learning 10-month-olds discriminated the intact lexical-tone contrast while French-learning 10-month-olds failed. However, only the French 10-month-olds discriminated degraded lexical tones when FM, and thus voice-pitch cues were reduced. Moreover, Mandarin-learning 10-month-olds were found to discriminate the pitch trajectories as presented in click trains better than French infants. Altogether, these results reveal that the perceptual reorganization occurring during the first year of life for lexical tones is coupled with changes in the auditory ability to use speech modulation cues.

The development of consonant and lexical-tone discrimination between 3 and 6 years: Effect of language exposure

“…For lexical tones, the same pattern has been observed at around the same age. Infants from a non-tone language background show a perceptual decline for non-native tones between 6 and 9 months, while infants from a tone language background do not show any decline for the same tone contrasts at the same age (Cabrera et al, 2015;Mattock & Burnham, 2006;Mattock, Molnar, Polka, & Burnham, 2008;Yeung, Chen, & Werker, 2012). However, a perceptual rebound for lexical-tone perception has recently been observed in the second year of life for non-native infants (Liu & Kager, 2014).…”

Monolingual and Bilingual Infants’ Ability to Use Non-native Tone for Word Learning Deteriorates by the Second Year After Birth

“…As for the attunement of lexical tones, tone-language learning infants maintain and improve their tonal sensitivity ( Harrison, 2000 ; Mattock and Burnham, 2006 ; Yeung et al, 2013 ; Shi et al, 2017a ; Tsao, 2017 ). Meanwhile, non-tone-language learning infants’ sensitivity to tones greatly decreases at 9 months ( Mattock and Burnham, 2006 ; Mattock et al, 2008 ; Liu and Kager, 2014 ; Cabrera et al, 2015 ; Shi et al, 2017b ).…”

Discrimination and identification of lexical tones and consonants in Mandarin-speaking children using cochlear implants

“…It is possible that adults may have learned to rely on specific acoustic information such as the fine spectro-temporal cues conveying fine voice-pitch variations in order to perceive lexical tones. Although Mandarin-speaking adults with NH experience difficulties in perceiving lexical tones when the fine spectrotemporal cues are degraded, in non-tone languages, such as French, listeners who have learned to rely on the envelope cues to detect tone differences do not have the same difficulties (Cabrera et al, 2014(Cabrera et al, , 2015. The children in the present study had congenital hearing loss and therefore had been listening to speech only through CI processors after implantation.…”

“…This crosslinguistic difference is also observed at 10 months of age; however, it is not observed at 6 months. This observation suggests that the duration of exposure to the native language does influence the use of the acoustic information of the speech signal (Cabrera et al, 2015). Interestingly, in those studies, French listeners (infants at 10 months and adults) were shown to be better able to use the remaining temporal envelope to discriminate non-native lexical tones compared to Mandarin listeners.…”

“…The children in the present study had congenital hearing loss and therefore had been listening to speech only through CI processors after implantation. In these specific listening conditions, children may have learned to rely on the remaining acoustic information (i.e., envelope cues) that conveys some pitch information (Cabrera et al, 2015;Wong et al, 2005). Children with CIs exposed to Mandarin may thus have developed efficient perceptual strategies to process lexical tones.…”