Bilingualism goes to school: The interplay of (extra)linguistic factors in successful bilingual development

移民使欧洲越来越多的语言，英国致力于促进这种语言的多样性，因为文化认同，社会融合和凝聚力（社会流动委员会，2022）。遗产语言是在这些家庭语言不是更大社会的主导语言的情况下在家里使用的少数民族语言。例如，波兰语、旁遮普语和葡萄牙语是英国广泛使用的传统语言。在2021/2022年，接近20%的小学生（160万名学生）在家里说的不是英语（教育部，2022年）。在国内说这些语言可以使移民儿童与父母的原籍国和文化遗产保持联系。与此同时，很明显，成功的融合还需要对社会的主要语言（英语）有很高的熟练程度（Hutchinson, 2018）。这个博士项目要解决的关键问题是，如何促进两种语言的发展，使这些多语言的公民能够利用日益一体化的欧洲带来的教育和职业机会。为了解决这个问题，我们将与一个主要的非学术利益相关者密切合作，葡萄牙Camões研究所，作为欧洲推动双语教育的主要机构之一，对了解促进双语发展的因素非常感兴趣。成功的双语发展有几个因素。这些因素包括习得年龄、通过不同的家庭关系与传统语言的接触程度、社会经济地位、正规学校教育和传统语言的明确语法教学（例如，Bayram等人，2021年；Torregrossa等人，2022年）。然而，大多数研究孤立地考虑变量，这意味着关键因素的相互作用及其对双语语言发展的影响尚未得到充分理解。此外，大多数研究观察到这些因素对传统语言的特定方面的习得的影响，而不是更广泛的语言特性。最后，大多数研究认为传统语言独立于主流语言。这是有问题的，因为我们需要研究使儿童能够发展两种母语的条件，而这需要测试他们两种语言的能力。博士项目的目标是通过直接解决这些缺陷，显著提高我们对决定成功双语发展的因素的理解。首先，我们不是孤立地考虑变量，而是研究上述关键因素在双语发展中的相互作用。其次，我们将观察三个语言领域（词汇、形态、句法）的发展，而不是仅仅关注语言的一个领域。第三，我们将研究这些因素对传统语言和主流语言的影响，而不是只观察这些因素对一种语言的影响。我们将把重点放在英葡双语发展上，作为一个测试案例，但这个博士项目的见解将适用于其他语言星座。

Migration is making Europe increasingly multilingual, and the United Kingdom is committed topromoting this linguistic diversity for reasons of cultural identity, social integration and cohesion(Social Mobility Commission, 2022). Heritage languages are the minority languages spoken athome in situations where these family languages are not a dominant language of the largersociety. For example, Polish, Punjabi, and Portuguese are widely spoken heritage languages in theUnited Kingdom. In 2021/2022, close to 20% of school pupils (1.6M pupils) spoke a languagedifferent than English at home (Department for Education, 2022). Speaking these languages athome permit migrant children to maintain ties to their parents' country of origin and to their cultural heritage. At the same time, it is clear that successful integration also requires a high levelof proficiency in the majority language of society (English) (Hutchinson, 2018).The key question, and one to be addressed in this PhD project, is how to promote thedevelopment of both languages so that these multilingual citizens can make use of theeducational and professional opportunities resulting from an increasingly integrated Europe. Inaddressing this question, we will work in close collaboration with a major non-academicstakeholder, Portugal's Camões Institute, which, as one of Europe's leading institutions promotingbilingual education, has a significant interest in understanding the factors that facilitate bilingualdevelopment.Several factors have been identified for successful bilingual development. These includethe age of acquisition, the amount of contact with the heritage language through different familyconstellations, socioeconomic status, formal schooling, and explicit grammar instruction in theheritage language (e.g., Bayram et al., 2021; Torregrossa et al., 2022). However, most studiesconsider variables in isolation, which means that the interplay of critical factors and their impacton bilingual language development are not fully understood. In addition, most studies observe theeffects of these factors on the acquisition of very specific aspects of the heritage language ratherthan a broader range of language properties. Finally, most studies consider the heritage languageindependent of the majority language. This is problematic as we need to study the conditions thatenable children to develop their two native languages, and this requires testing their competencein both. The objective of the proposed PhD project is to significantly advance our understanding ofthe factors that determine successful bilingual development by directly addressing theseshortcomings. First, rather than considering variables in isolation, we will examine the interplay ofthe critical factors above in bilingual development. Second, rather than focusing on just onedomain of language, we will observe the development of three linguistic domains (lexicon,morphology, syntax). And third, rather than observing the effect of these factors on just onelanguage, we will investigate their effect on both the heritage and the majority language. We willfocus on English-Portuguese bilingual development as a test case, but the insights from this PhDproject will apply to other language constellations.