The vocabulary size of 16- to 30-month-old children ( N = 1235) was assessed using the Estonian adaptation of the MacArthur–Bates Communicative Development Inventory: Words and Sentences (ECDI-II). The relationship between children’s expressive vocabulary size and different factors of the child and his/her social environment was examined. Results confirm the findings of studies from other languages showing that girls have larger vocabularies than boys, and first-born children are at an advantage compared to later-born children. Children of highly educated parents have bigger vocabularies than children whose parents have a lower educational level; this effect was significant for both maternal and paternal education. It was found that children of less-educated fathers who spend a high amount of time per week (> 40 hours) in daycare have smaller vocabularies than children of fathers with higher educational attainment.

The study examined adolescents' strategies for managing hypothetical conflicts with the same-sex best friend and their reasons behind these strategies. The sample included 905 14-year-old Estonian adolescents. The findings indicated that negotiation was the most frequently suggested strategy by adolescents. At the same time, adolescents' strategies and reasons strongly depended on the source of conflict. Coercive strategies and self-oriented reasons were more common in case of severe conflicts that could damage interpersonal relatedness or pose a threat to the attainment of autonomy. Girls reported having conflicts more frequently and suggested more negotiation than boys in all conflict situations. Sex differences did, however, occur only in adolescents' strategies. Boys' and girls' reasons behind their strategies were similar. Implications will be discussed.

Purpose The purpose of the current study is to develop a valid and reliable screening tool to identify children with risk of developing language difficulties for Estonian-speaking 2- to 3-year-old children. Method Nine hundred ninety parents of children ages 1;8–3;1 (years;months) filled in the Estonian MacArthur-Bates Communicative Development Inventory II (ECDI-II SF)—containing a 100-word vocabulary checklist, questions about decontextualized language use, and sentence production. A subset of parents filled in the long form of the MacArthur-Bates Communicative Development Inventory: Words and Sentences ( n = 131). We examined the results of 31 children with language problems on the ECDI-II SF to assess the accuracy of the instrument. Results The concordance of scores on the ECDI-II long form and ECDI-II SF is high. Toddlers' results on the ECDI-II SF are related to their gender, with girls outscoring boys on the expressive vocabulary and sentence complexity subscales. We also found that children of highly educated mothers outperform others in the acquisition of grammatical skills. The sensitivity and specificity of the ECDI-II SF vocabulary section supported the implementation of this screening tool in order to identify toddlers with difficulties in their language development. Conclusions ECDI-II SF vocabulary scores are the most informative for determining whether a 2- or 3-year-old is following typical developmental patterns or should be referred to a speech and language specialist for a direct assessment. We provide a discussion on early language screening process and its implications for public health policies.