In first language acquisition research, investigations on the semantics and lexicon of the child are often conducted by measuring brain activity at the surface of the scalp (EEG). Such EEG studies have shown different brain reactions to matching and mismatching pairs of pictures and words from 19-month-olds (Friedrich & Friederici, 2005). Similarly, results from 20-month-olds exposed to auditory stimuli only indicated different brain reactions to correct pronunciations and mispronunciations (Mills et al., 2004). However, these studies do not take the typical production patterns in that specific age into account.
In the present study, we measured brain reactions of 13 24-month-olds exposed to pairs of pictures and words in four different conditions: correctly pronounced words, two different kinds of mispronounced words, and novel words. The first type of mispronunciations (M1) consisted in minor mispronunciations consistent with typical production patterns in first language acquisition, e.g. ‘ko’ instead of ‘sko’ (shoe). The second type (M2) was characterized by phonological changes that are not expected at 24 months, e.g. ‘fo’ instead of ‘sko’ (shoe). The novel words consisted of phonotactically possible Swedish non-words.
A principal component analysis (PCA) decomposition of the EEG data showed two patterns of posterior negativity typical of lexical-semantic processing: one for novel words in comparison to the other conditions, and the other for novel and M2 word forms compared to M1 and correct word forms. These results indicate that M1 are processed similar as correct word forms, and that M2 and novel words are processed alike. However, while these patterns were visually salient in successive components, the results were not statistically significant. We suspect that the non-significant results were due to the small dataset. Nevertheless, this study contributes to the discussion on the relationship between perception and production in first language acquisition.
WILD 2015 - Workshop on Infant Language Development, Stockholm, June 10-12, 2015