Vulnerability in heritage speakers of Spanish in the Netherlands An interplay between language-internal and language-external factors

This dissertation investigates the acquisition of Spanish as a heritage language from a linguistic perspective. The main objective is to locate and explain vulnerability in heritage grammars. The relative vulnerability of internal and external interfaces is tested in a unique and novel way, namely by comparing interfaces within phenomena, so as to keep other possibly intervening variables constant. Data from acceptability judgment tasks and elicited production tasks targeting mood and subject position reveal that syntax is the most robust domain, while the external interface between syntax and discourse-pragmatics is most vulnerable, in line with the Interface Hypothesis.
This thesis moreover provides an important contribution to the field by investigating a relatively understudied population of heritage speakers, and shows that the specific socio-linguistic circumstances of the host country, as well as the linguistic properties of the majority language spoken there, can have important effects on the heritage language. Others variables, such as the specific task that is used, the type of knowledge that is targeted (implicit or explicit), the amount of input received in early childhood, the age at which testing takes place (in childhood vs. in adulthood), and the age of onset of the weaker language (heritage vs. L2 speakers) are also shown to influence the degree and the type of vulnerability. As such, this dissertation demonstrates that heritage language acquisition is a highly complex phenomenon, in which various language-internal and language-external factors are intertwined in an intricate way.