Children discover the spectral skeletons in their native language before the amplitude envelopes.

Abstract

Much of speech perception research has focused on brief spectro-temporal properties in the signal, but some studies have shown that adults can recover linguistic form when those properties are absent. In this experiment, seven-year-old English-speaking children demonstrated adult-like abilities to understand speech when only sine waves replicating the three lowest resonances of the vocal tract were presented, but failed to demonstrate comparable abilities when noise bands amplitude-modulated with envelopes derived from the same signals were presented. In contrast, adults who were not native English speakers, but were competent second language learners, were worse at understanding both kinds of stimuli than native English-speaking adults. Results showed that children learn to extract linguistic form from signals that preserve some spectral structure, even if degraded, before they learn to do so for signals that preserve only amplitude structure. We hypothesize that children's early sensitivity to global spectral structure reflects the role that it may play in language learning.

Does harmonicity explain children’s cue weighting of fricative-vowel syllables?

“…Of course, signals in this second experiment, as well as those in Nittrouer et al ͑2009͒, shared another attribute. In both cases they were constructed entirely of noise.…”

“…In both cases they were constructed entirely of noise. That means that possibly the shift away from weighting formant transitions strongly demonstrated by this experiment and by the poor sentence recognition found in Nittrouer et al ͑2009͒ for noisy stimuli might be attributable to children failing to attend to noise components in speech signals. The current study cannot really separate the contributions made to children's results of broadened bandwidths and noisy signals.…”

“…Previously it was hypothesized that this perceptual strategy is preferred early in life because these global, recurrent patterns of structure help children isolate linguistically significant stretches, such as words ͑e.g., Jusczyk, 1993;Nittrouer et al, 2009;. However, careful scientific inquiry dictates that all alternative explanations be explored before accepting just one.…”

Toddlers' comprehension of degraded signals: Noise-vocoded versus sine-wave analogs

“…Yet Nittrouer and colleagues (Nittrouer and Lowenstein, 2010;Nittrouer et al, 2009) found that the ability to interpret these NV speech and sine-wave analogs had different developmental time courses. Relative to adults, children aged 3-7 yr had much greater difficulty with NV speech than with sine-wave speech.…”

“…The authors interpreted these results as indicating that children rely on dynamic spectral information to a greater extent than do adults and thus have particular difficulty with NV signals that lack such information. Or, to put it another way, children learn initially to focus on spectral information and thus "learn to extract linguistic form from signals that preserve some spectral structure" earlier in development (Nittrouer et al, 2009(Nittrouer et al, , p. 1245. Such results have implications for children hearing speech through cochlear implants, at least if normal-hearing children's performance with NV speech serves as a model for children's performance with an actual implant.…”