Consonant and Vowel Processing in Word Form Segmentation: An Infant ERP Study

Abstract

Segmentation skill and the preferential processing of consonants (C-bias) develop during the second half of the first year of life and it has been proposed that these facilitate language acquisition. We used Event-related brain potentials (ERPs) to investigate the neural bases of early word form segmentation, and of the early processing of onset consonants, medial vowels, and coda consonants, exploring how differences in these early skills might be related to later language outcomes. Our results with French-learning eight-month-old infants primarily support previous studies that found that the word familiarity effect in segmentation is developing from a positive to a negative polarity at this age. Although as a group infants exhibited an anterior-localized negative effect, inspection of individual results revealed that a majority of infants showed a negative-going response (Negative Responders), while a minority showed a positive-going response (Positive Responders). Furthermore, all infants demonstrated sensitivity to onset consonant mispronunciations, while Negative Responders demonstrated a lack of sensitivity to vowel mispronunciations, a developmental pattern similar to previous literature. Responses to coda consonant mispronunciations revealed neither sensitivity nor lack of sensitivity. We found that infants showing a more mature, negative response to newly segmented words compared to control words (evaluating segmentation skill) and mispronunciations (evaluating phonological processing) at test also had greater growth in word production over the second year of life than infants showing a more positive response. These results establish a relationship between early segmentation skills and phonological processing (not modulated by the type of mispronunciation) and later lexical skills.

Emergence of a consonant bias during the first year of life: New evidence from own‐name recognition

“…Based on previous evidence from word segmentation (Nishibayashi & Nazzi, 2016; Von Holzen et al, 2018), we may expect 8‐month‐olds to show a consonant bias during own‐name recognition. However, word form segmentation only requires the short‐term retention of a word form, whereas word form recognition requires the long‐term maintenance of a word form.…”

“…Finally, to capture the developmental consequences of individual variation in the emergence of the consonant bias, we sent follow‐up vocabulary questionnaires to the 8‐month‐old infant participants when they were 13, 16, and 24 months of age. Sensitivity to both vMPs and cMPs in word segmentation at 8 months has been found to predict growth in word production over these ages (Von Holzen et al, 2018). In the current study, however, we measure the preference for consonant compared with vowel information, which may provide a more accurate assessment of whether consonant bias emergence is related to later vocabulary outcomes.…”

“…The emergence of the consonant bias may therefore reflect development of a sophisticated understanding of the speech in an infants’ native language and has been proposed as a bootstrapping mechanism for early language acquisition. For children learning French, the language where this has been most studied and also the language we focus on in the current study, evidence for the consonant bias in older infants and toddlers has been robust (Havy & Nazzi, 2009; Havy, Serres, & Nazzi, 2014; Nazzi, 2005; Nazzi & Bertoncini, 2009; Nazzi, Floccia, Moquet, & Butler, 2009; Nazzi & New, 2007; Zesiger & Jöhr, 2011) and has been extended to the first year of life, in infants as young as 8 months in word segmentation (Nishibayashi & Nazzi, 2016; Von Holzen, Nishibayashi, & Nazzi, 2018) and 11 months in familiar word form recognition (Poltrock & Nazzi, 2015). By examining younger infants, however, two studies have established that for French‐learning infants, an initial vowel bias remains until at least 5 months for own‐name recognition (Bouchon, Floccia, Fux, Adda‐Decker, & Nazzi, 2015) and 6 months for word form segmentation (Nishibayashi & Nazzi, 2016).…”

“…Thus far, only one study has directly examined the timing of consonant bias emergence using the exact same stimuli and method. In a series of word form segmentation experiments, Nishibayashi and Nazzi (2016) examined the emergence of the consonant bias with 6‐ and 8‐month‐old French‐learning infants, finding a vowel bias in 6‐month‐olds but a consonant bias in 8‐month‐olds (see Von Holzen et al, 2018 for similar ERP results with 8‐month‐olds). Other indirect evidence comes from another type of lexical processing, familiar word form recognition.…”

Infants’ statistical word segmentation in an artificial language is linked to both parental speech input and reported production abilities

“…Understanding links between mechanisms of word segmentation and individual variability is important, because many researchers have shown that performance in speech segmentation tasks is highly predictive of later vocabulary learning (Junge & Cutler, 2014;Newman, Ratner, Jusczyk, Jusczyk, & Dow, 2006;Singh, Steven Reznick, & Xuehua, 2012;Von Holzen, Nishibayashi, & Nazzi, 2018).…”