- Boon, Erin Diane. 2014. Heritage Welsh: a study of heritage language as the outcome of minority language acquisition and bilingualism, Doctoral dissertation, Harvard University, texte.
"Part I investigates topics which are pertinent to the study of heritage language—its definition and connection to the Critical Period Hypothesis, the distinction between incomplete language acquisition and attrition, and theories of bilingual language systems. Part II details the analysis of the heritage Welsh samples in particular. The concluding remarks broaden the focus to the minority status of the baseline language in Wales, presenting the inevitability of heritage speakers there as well if childhood exposure to Welsh does not reach the critical level necessary for full native proficiency and if the language is not maintained in adulthood. This project introduces the terms “heritage Welsh” and “heritage speaker” into Welsh linguistics, and presents a framework with which to discuss this previously neglected category of bilinguals."