What do you think? The relationship between person reference and communication about the mind in toddlers

The present studies examined the relationship between children's use of grammatical structures indicating self–other differentiation (i.e., personal pronouns, verb conjugation) and their ability to use language to express their own and others' mental states (MSL). In Study 1, 104 parents of two- to three-year-old children filled out online checklists assessing children's vocabulary, their use of MSL, and first- and second-person pronouns and verb forms. In Study 2, 77 mothers of 1.5- to 2.5-year-old children filled out the MacArthur–Bates communicative development inventory, and additional checklists for MSL and verb conjugation. Results of both studies showed that children's use of grammatical person reference is strongly related to their level of grammatical abilities. Importantly, pronominal and inflectional references to others were correlated with children's discourse about the mind. Thus, linguistic tools that are used to distinguish self from others are not only indicators of children's grammatical development, but also their level of sociocognitive understanding.