The keynote article “Grammatical processing in language learners” by Clahsen and Felser, aimed to compare the grammatical processing in adult native speakers, child first language learners, and adult second language learners (L2ers) (3). The authors examined works that observed the processing of morphology, ambiguous sentences, and syntactic dependencies before going into their general discussion in which they summarize the results and suggest the shallow structure hypothesis.
The first topic looked at by Clahsen and Felser was morphological processing. Native adult speakers (L1ers) use two methods for processing: lexical storage and morphological decomposition (5). The authors wanted to know if children and L2ers use the same processing techniques. For children, they found that they did, indeed, use the same processing techniques as native adult speakers. A study on the production of high and low frequency German regular and irregular participle forms (6). It was found that like native adults, children produced high-frequency irregular participles faster than low-frequency one and high-frequency regular participles slower than low-frequency ones (7-8). A second study on comprehension of German noun plurals looked at ERP waveforms of children and adults while they listened to German irregular/incorrect and regular/correct plural forms (8) Again both adults and children showed similar results: “frontal negativity followed by a centroparietal positivity” (9).
Clahsen and Felser explain that the only difference is speed, which possibly attributed to incomplete acquisition and/or slower lexical access (12). For L2ers, Clahsen and Felser looked at a study by Hahne which looked at ERPs of Russian L1 speakers who had acquired German as their second language to see how they processed inflected German participles and noun formation on-line (10). Participants also completed two stimulated production tasks where they had to give the corresponding participle and noun plural forms of uninflected verbs and nouns. Results of the ERP and production tasks showed that L2ers also use the same processing techniques as native speakers. Small differences between the two groups are likely because of proficiency (11). Clahsen and Felser concluded that L2ers with high proficiency are able to use the same two morphological processing techniques that are used by native speakers (12).
The second topic addressed is ambiguous sentence processing. A previous study by Felser looked at how children and adults, “processed relative clause attachment preferences in sentences” in English. Native adult speakers’ results showed that the type of attachment preferred by the adults depended on the type of preposition joining two NPs (14). Children’s attachment, however, were not dependent on the type of preposition. Instead, it dependent on their working memory spans. Those with high-span working memory preferred NP1 attachment, while those with low-working memory span preferred NP2...