Charting the route of bilingual development: contributions from heritage speakers’ early acquisition

The study of early bilingual acquisition in heritage languages continues to be a valuable source of theoretical and empirical evidence for both general linguistic theory and acquisition theory. The articles featured in this special issue corroborate this by providing new data and analysis in a number of key morphosyntactic and prosodic areas of Romance languages, offering new insights to long-standing issues in bilingual acquisition. Specific areas include, interface vulnerability as a source of problems in bilingual children’s acquisition, incomplete acquisition as an explanation for heritage speaker’s non-target language, the effects of quality and frequency of input exposure in bilingual children and the effects of language contact on language acquisition. In this commentary, the main findings, contributions and merits of the articles are discussed in the context of language development and bilingual acquisition; links with existing relevant discussions and debates are highlighted; and possible paths for future research are suggested