This study focuses the nature of sentential subjects by comparing heritage English speakers (2L1) with monolingual English (L1) and L2 English speakers. It aims to determine whether typological similarity is a significant factor related to crosslinguistic influence (CLI). Previous research (e.g., Liceras et al., 2012; Valdés, 2000) suggests that heritage speakers exhibit characteristics of both L1 and L2 speakers, depending on the grammatical properties analyzed and their instantiation in the bilinguals' languages. This study provides evidence that CLI is depends on the quantity and quality of linguistic input, where the dominant language influences the non-dominant language. Additionally, typological similarity and grammatical saliency are shown to play crucial roles in language acquisition and learning.
