Tomas, E. & Liaukovich, K.
National Research University Higher School of Economics
Grammatical morphemes are typically acquired in a specific order and by a certain age, marking the milestones in children?s morphosyntactic development. These milestones correspond to how long children?s sentences tend to be, i.e., the Mean Length of Utterance (MLU) (Brown, 1973). However, these norms are language-specific, and for comparing the MLU indices and the stages in morphosyntactic development cross-linguistically more data on typologically diverse languages are needed (Allen & Dench, 2015). Specifically, little is known about how MLU should be adjusted for morphologically rich languages like Russian; for example, by averaging the number of syllables, morphemes or words?
This paper reports on a cross-sectional study with 30 native speakers of Russian aged 2;6-5;6 years. Children?s spontaneous speech was audio-recorded during a one-on-one play session with a researcher. For each child the first 100 intelligible utterances were transcribed and analysed using linear mixed effects models. The analysis estimated children?s MLU (in syllables/morphemes/words), the diversity of grammatical morphemes, the number of different words and the overall syntactic complexity. The detailed approach for using MLU measurements in Russian and for building developmental trajectories of morpheme acquisition using cross-sectional data are discussed.