Quantifying the relative contributions of lexical and phonological factors to regular past tense accuracy

Purpose: Children with specific language impairment (SLI) frequently have difficulty producing the past tense. This study aimed to quantify the relative influence of telicity (i.e. the completedness of an event), verb frequency and stem final phonemes on the production of past tense by school-age children with SLI and their typically-developing (TD) peers.

Method: Archival elicited production data from children with SLI between the ages of 6-9 and TD peers aged 4-8 were re-analysed. Past tense accuracy was predicted using measures of telicity, verb frequency measures and properties of the final consonant of the verb stem.

Result: All children were highly accurate when verbs were telic, the inflected form was frequently heard in the past tense and the word ended in a sonorant/non-alveolar consonant. All children were less accurate when verbs were atelic, rarely heard in the past tense or ended in a word final obstruent or alveolar consonant. SLI status depressed overall accuracy rates, but did not influence how facilitative a given factor was.

Conclusion: Some factors that have been believed to be useful only when children are first discovering past tense, such as telicity, appear to be influential in later years as well.