Neural Indices of Vowel Discrimination in Monolingual and Bilingual Infants and Children.

The study did not assign children to language groups or give treatment, so it cannot show that changing exposure improves speech perception. Socioeconomic status was not matched across groups, and the bilingual subgroup with more English exposure had lower socioeconomic status than the other groups. The results come from one English vowel contrast, so they may not apply to other speech sounds, languages, or language pairs. Spanish and English are prosodically different, so the findings may not generalise to bilingual children learning more similar languages. Some hearing screening data were incomplete, and children were excluded for refusal, missing or corrupt data, too few usable trials, or suspected language impairment. The study reports neural responses, not behavioral speech discrimination, language diagnosis, or therapy outcomes.

No conflict-of-interest declaration is provided in the supplied text. The article is listed as supported by NIH extramural research funding.

Do not conclude that bilingual children have a speech perception disorder or that increasing English exposure will improve speech. The study measured brain responses in a research task, not clinical outcomes, and children with more English exposure only resembled monolingual children on the early neural measure.