Age-of-acquisition effects in native speakers and second-language learners

Two lexical decision experiments were conducted to study the locus of age-of-acquisition (AoA) effects in skilled readers with English or Dutch as their first language. AoA effects have generally been explained in terms of phonological processing. In Experiment 1, Dutch elementary school and secondary school students were presented with words factorially manipulated on surface frequency and AoA). Two main effects and an interaction were found, confirming findings reported for English speakers by Gerhand and Barry (1999). In addition, a language development effect was established: AoA effects decreased with reading age. Elementary school students showed the largest AoA effects. Experiment 2 used two groups of subjects. The first group consisted of Dutch students enrolled in a master's degree program in English. The second group consisted of native speakers of English. All subjects were presented with the experimental set of words used by Gerhand and Barry (1999). British subjects showed the same response pattern as reported by Gerhand and Barry (1999). The question of interest was whether Dutch subjects would show an AoA effect on the English set or not. The answer was affirmative. Dutch subjects produced identical response patterns as the British group, showing only an overall 94-msec latency delay. This result challenges predictions of the phonological completeness hypothesis. Alternative accounts in terms of semantic processing are discussed.