An ERP-study of German 'irregular' morphology

The plural morphology of German is characterised by five different plural allomorphs (-(e)n, -e, -er, -s, zero), partly combined with changes in the vowel (umlaut). While in former studies the -s plural allomorph is identified as the regular plural, the remaining forms are categorised as irregular. These observations have been discussed within the framework of the dual mechanism model. One component contains a rule for regular inflection; it provides the default. The second component is designed as a network and hosts irregular plural forms. However, as noted by several linguists, the so-called irregular component of German plural morphology is more structured and contains more predictable plural forms than the dual mechanism model predicts to be the case. Therefore, some plural forms should be less dependent on a network system. Using the technique of event-related potentials, cognitive processing of different irregular German plural allomorphs is investigated in this study. Comparisons include irregular allomorphs with low and high predictability, i.e. true irregulars were compared to subregularities. Indeed, the plural forms identified as subregulars showed a difference in processing by inducing a reduced N400 over right posterior medial electrodes. Up to date, the dual mechanism model treats different so-called irregular forms alike. But in light of these new findings, the network component of the dual mechanism model needs to be refined.