How Finnish morphology confuses the L2 speaker

Finnish morphology is notoriously difficult for L2 speakers. The rich inflectional paradigms and the abundant compound possibilities enforces anybody who wishes to be even a moderate proficient language user in Finnish to quickly develop morphological knowledge and awareness in this language. The current study investigates to what extent this development is complicated by morphophonological variation in the inflectional paradigms. That is, in Finnish the word stem frequently changes when it is combined with inflectional suffixes, e.g., tauko 'break' => tauolla 'at the break' or sota 'war' => sodan 'the war's'. These changes obscure the stem and may make the decomposition process - segmenting the morphologically complex word into constituent morphemes (tauo+lla; as Finnish-speakers usually do, see Bertram, Laine, Karvinen, 1999) - very complex. The current study tested 38 native speakers and 34 L2-speakers in a visual lexical decision experiment including monomorphemic nouns (e.g., kaupunki 'city'), inflections without stem changes, e.g., loma 'holiday' => lomalla 'on holiday') and inflected words with stem changes (e.g., tauolla 'at the break'). The results showed the standard delay in inflectional processing but this delay was enlarged in case of stem changes for both L1 and L2 speakers. However, whereas for L1 speakers the error rates were low across conditions (1 to 2 %), L2-speakers made much more mistakes with inflections including stem changes than for monomorphemic nouns or 'normal' inflections. The results underline the notion that sophisticated ideosyncratic language peculiarities greatly confuse the L2-speaker and that these peculiarities require extra attention in educational settings.