Speeded production of inflected words in children and adults.

This study examines the production of regular and irregular participle forms of German with high and low frequencies using a speeded production task. 40 children in two age groups (five- to seven-year olds, eleven- to twelve-year olds) and 35 adult native speakers of German listened to stem forms of verbs presented in a sentential context and were asked to produce corresponding participle forms as quickly and accurately as possible. Dependent variables were the subjects' participle-production latencies and error rates. We found contrasts between the production of regular and irregular forms in both children and adults, with respect to the production latencies and types of morphological error. Children overapplied the regular patterns to forms that are irregular in the adult language, but not vice versa. High-frequency irregular participles were produced faster (and amongst the children more accurately) than low-frequency ones, whereas regular participles yielded a reverse frequency effect, i.e. longer production latencies for high-frequency forms than for low-frequency ones, in the two groups of children as well as in one subgroup of adults. We explain these findings from the perspective of dual-mechanism models of inflection arguing that the mental mechanisms and representations for processing morphologically complex words ('words' and 'rules') are the same in children and adults, and that the observed child/adult differences in participle production are due to slower and less accurate lexical access in children than in adults.