In this article, we propose that elements of heritage language grammars—both in the form of axiomatic features and larger combined representational units—are not easily lost over the course of the lifespan. This view contrasts with alternative explanations for the steady-state representation of these grammars that suggest truncated acquisition or erosion are the primary culprits of perceived language loss. In production and comprehension processes for heritage bilinguals, particular elements are more difficult to access than others, leading to differential ways to access representations and feature values. To illustrate and support this hypothesis, we build on previous work by examining the interpretation and use of obligatory mood selection in Spanish desiderative constructions in three groups of heritage speakers with different levels of language proficiency.

The rise of scientific inquiry focusing on bilingualism over the past few decades has also borne witness to an increase in the study of individuals and communities who speak a native language that is not the sociolinguistically dominant language of the environment in which they grew up. While it is common practice to refer to these diverse groups and individuals as “heritage speakers”, it is unclear whether it is appropriate to classify all of them under the same terminology. In this chapter, we take a closer look at three different groups: (i) children, (ii) young adults, and (iii) elderly, moribund bilinguals who have all been referred to as heritage speakers in the literature. After exploring aspects of phonological, (morpho)syntactic, and semantic/pragmatic developments, we show that a great deal of symmetry exists between them, thus justifying the cohesive, overarching label of “heritage speakers” to all three sub-groups. Finally, we outline what this broader definition of heritage speakers means for long-standing debates in the literature, such as those that concern the acquisition, development, and maintenance of the heritage grammar across the lifespan.

On the surface, bi- and multilingualism would seem to be an ideal context for exploring questions of typological proximity. The obvious intuition is that the more closely related two languages are, the easier it should be to implement the two languages in one mind. This is the starting point adopted here, but we immediately run into the difficulty that the overwhelming majority of cognitive, computational, and linguistic research on bi- and multilingualism exhibits a monolingual bias (i.e., where monolingual grammars are used as the standard of comparison for outputs from bilingual grammars). The primary questions so far have focused on how bilinguals balance and switch between their two languages, but our perspective on typology leads us to consider the nature of bi- and multi-lingual systems as a whole. Following an initial proposal from Hsin (2014), we conjecture that bilingual grammars are neither isolated, nor (completely) conjoined with one another in the bilingual mind, but rather exist as integrated source grammars that are further mitigated by a common, combined grammar (Cook, 2016; Goldrick et al., 2016a,b; Putnam and Klosinski, 2017). Here we conceive such a combined grammar in a parallel, distributed, and gradient architecture implemented in a shared vector-space model that employs compression through routinization and dimensionality reduction. We discuss the emergence of such representations and their function in the minds of bilinguals. This architecture aims to be consistent with empirical results on bilingual cognition and memory representations in computational cognitive architectures.