Adult language learners also tend to overregularize morphological and syntactical patterns, however unlike children’s overregularization, the overregularization in adult learners remain in their system and adult learners do not grow out of it (Kam et al., 2005).
One example of this is from a study on adult learners of German observed by Klein and Perdue (1993),would be how adult learners of german uses the indefinite article ‘eine’ (which denotes plurarity and feminine form) indiscriminately even though German has many indefinite article forms are used in correspondence with the gender of the noun (these genders can also be masculine or neuter).
The presence of Low Frequency Verbs
In addition, the dual mechanism model mentioned in the overregularization in children takes place in adults as well. It goes without saying that the more practice a speaker gets with the language the better the retrieval however in cases such as low frequency verbs, due to the less frequent contact, retrieval may fail and hence rule would be executed. For example low frequency verbs such as leapt and dove may be said as ‘leaped’ and ‘dived’ instead, due to the lack of contact with the irregular forms.
Complex Input
In addition, adults also tend to overregularize more when the input is more complex. Adults tend to overuse morphemes on nonobligatory context for example, a perfective form is used instead of an imperfective aspect.
“As a boy I went to New york” (perfective: has end point)
“As a boy i used to go to New york” (imperfective: does not really have an end point)
This can be explained by how the second language is interfered by the native language. The learning of the second language is made more difficult with the interference by the native language. Because grammatical rules are set in place while acquiring the native language but both native and second language may not share a similar set of grammatical rules hence it cannot be applied throughout.