The early use of first and second person pronouns has been viewed as a sign of emerging social understanding. However, it may also depend on general language development: pronouns do not appear among the first words children acquire. In addition, some languages conjugate verbs for person, and the inflections may thus show similar relations to social understanding and language as pronouns. Very few studies have examined the relations between early person reference on the one hand and both social understanding and language development on the other. The present study used data on spontaneous language transcripts and language tasks from 58 Czech-speaking children aged 30 months to examine the relations between person reference, social understanding, and general language development. Social understanding was estimated from children's use of the mental state language (MSL). The results confirm that both MSL and general language development show unique relations to person reference with pronouns as well as verbs.