Finnish noun inflections and the FLH from two perspectives

Abstract Through a consideration of the noun inflections of Finnish, we examine Butterworth’s (1983) full-listing hypothesis (FLH), that whole-word forms are stored in the mental lexicons of language learners/users. While previous studies have consistently confirmed that complex derivational constructions are stored/retrieved this way in Finnish, the current consensus is that the inflectional forms are not, primarily because of the extremely large number that Finnish grammar projects. We challenge this reasoning in favor of a new theory that posits a dual lexicon for inflections, one for the full forms of stems and a parallel one for inflectional affix strings. To test this, we performed a segmentation experiment assessing the relative salience of morpheme and syllable boundaries in Finnish nouns, and also examined a large corpus of quasi-natural spoken dialogues for further evidence. Together, our findings demonstrated that the salience of the boundaries we examined was consistent with our expectations, that the number of inflected forms used in our corpus was only a tiny fraction of those predicted by rule, and that their productivity was highly correlated with their frequencies. While this evidence does not fully confirm the dual lexicon hypothesis, it does strongly indicate that no online grammatical rules are involved.