The study compares the acquisition of Estonian, Finnish and Sami compound nouns at an early stage of children’s linguistic development. The material derives from the spontaneous speech data collected during a longitudinal study of six children aged 1;3–3;1. Acquisition of compound word formation is analysed from the aspects of the emergence of first compound words in a child’s speech, acquisition of different patterns of compounding, independent formation of compound words, semantic transparency, and the role of the frequency of different compounding patterns in the input language.
In the three cognate languages investigated acquisition of compound word formation is rather similar, beginning at an early age, either at the end of the premorphological period or at the beginning of the protomorphological period at the age of 1;5–1;10. There is clear evidence that the first patterns of compounding emerging in children’s use are those on top of the frequency list of the input language. Most of the earliest compound words are semantically transparent. Language-specific traits are observed at the earliest stage of compound word acquisition. The child learning Sami, for example, used numerous compound nouns with a shortened front component quite from the start, as well as many compound nouns differing in the case of the front component. In the case of all three languages compound word formation is acquired as a productive system, enabling separate use of compound word components and occasional compounding actively practised by the young speakers.
As proved for several other languages, Indo-European included, input language is the most important factor in the early acquisition of the patterns of compound word formation, while the most frequent compounding patterns are the first acquired.