Morphological Productivity in Children With Normal Language and SLI

Abstract

Children with specific language impairment (SLI) are known to display persistent difficulties with inflectional morphology--in particular, the overuse of unmarked grammatical forms (i.e., zero-marking). Yet, several recent studies have shown that English-speaking children with SLI, like their normal language peers (NL), demonstrate a considerable degree of productive language abilities (e.g., Bishop, 1994; Loeb & Leonard, 1991; Oetting & Horohov, 1997). In this study, we explore productivity in the English past tense in school-age children with SLI (N= 31) and NL (N = 31) who were equivalent as a group in chronological and mental age. Although children in both groups produced a range of error types, the children with SLI produced significantly more errors, with a greater proportion resulting from zero-marking (e.g., go) than suffixation (e.g., goed). Item analyses indicated that suffixations and zero-markings were predicted by item frequency, phonological features of stems, and similarity relationships across items (i.e., neighborhood structure) in both groups, yet children with SLI were more sensitive to item phonology than their NL peers. Results are interpreted in light of the predictions of dual- versus single-mechanism models of morphological productivity. Implications for accounts of SLI are discussed.

Phonological Constraints on Children’s Production of English Third Person Singular – s

“…Thus, adding another syllable to the inflected word is apparently more difficult than having a consonant cluster (see similar findings by Marchman, Wulfeck, & Weismer, 1999).…”

Phonotactic probability and past tense use by children with specific language impairment and their typically developing peers

“…those showing over-regularizations such as throwed) in illustrating that children with SLI possess some degree of knowledge of past tense use in spite of their limited skill in this area (e.g. Eyer & Leonard, 1995;Oetting & Horohov, 1997;Marchman et al, 1999).…”

“…For example, Oetting and Horohov (1997), Marchman, Wulfeck, and Ellis Weismer (1999), Norbury, Bishop, and Briscoe (2001), and van der Lely and Ullman (2001) have all reported that children with SLI were more likely to use past tense with frequently occurring verbs than with infrequently occurring verbs. However, other findings have not been uniform across the studies.…”

The retreat from overgeneralization in child language acquisition: word learning, morphology, and verb argument structure

“…Again, some form of contrast, pre-emption or blocking (the term used with a slightly more specific meaning here than in the discussion above) seems to play an important role. A number of studies [23][24][25] have demonstrated a negative correlation across verbs between the rate of overgeneralization error and the relative or absolute frequency of the correct form (e.g., went, threw, slept, and sat).Again, though, pre-emption cannot be the whole story, as it cannot explain performance with novel items, for which no pre-empting past-tense form can be stored in memory. One possibility [26][27][28] is that children set up a rule for regular verbs (e.g., add -ed) and simply memorize the exceptions as a fixed list of stems to which a particular irregular rule applies (e.g.,…”

“…Again, some form of contrast, pre-emption or blocking (the term used with a slightly more specific meaning here than in the discussion above) seems to play an important role. A number of studies [23][24][25] have demonstrated a negative correlation across verbs between the rate of overgeneralization error and the relative or absolute frequency of the correct form (e.g., went, threw, slept, and sat).…”