Associations between early lexical composition and pre-reading skills at 5 years-A longitudinal study

Background: At the end of the second year, children's lexical compositions (LexC) differ significantly in terms of variety of lexical categories (nouns, verbs, adjectives, closed-class words). The aim of this study was to inves-tigate whether this variation is associated with acquisition of pre-reading skills (PreRS) at 5;0. Aims: To study the associations between LexC at 2;0 and PreRS at 5;0 and to examine the possible explaining value of LexC and lexicon size for PreRS.Participants and methods: Participants were 66 healthy, monolingual Finnish speaking children. LexC was measured at 2;0 using the standardized Finnish long form version of the MacArthur Communicative Develop-mental Inventory (FinCDI). Raw scores and percentages of words were used in the analysis. At 5;0, PreRS var-iables of letter knowledge, rapid automatized naming (RAN), lexical ability and phonological processing were collected.Results: The number of social terms, nouns, verbs, adjectives and closed class words associated significantly with all PreRS except RAN. The percentages of predicates and closed class words were positively associated with PreRS. All LexC variables and lexicon size at 2;0 had significant predictive values for the composite pre-reading score, explaining 19-32 % of the variation. The best model to explain PreRS included the number of nouns as the linguistic variable. A high percentage of social terms at 2;0 proposed weak PreRS at 5;0.Conclusions: LexC at 2;0 is a significant predictor of PreRS at 5;0. Closer examination of lexical composition is important, when assessing lexical skills at the end of the second year.