Conclusions: These findings extend positional effects on morpheme production to plural –s. An effect of coda complexity was not observed for plural but was observed for 3rd person singular, which raises the possibility that the morphological representation proper influences the degree to which phonological factors affect morpheme production.
The objective of the study was to identify the factors that determine the preservation/impairment of prepositions in aphasia. Five parameters derived from previous research ([Bennis et al., 1983], [Friederici, 1982], [Grodzinsky, 1988], [Kean, 1977], [Kean, 1979] and [Kreindler and Mihãilescu, 1970]) were examined in a sentence completion task and three types of grammaticality judgement tasks using four subcategories of prepositions with 18 preposition tokens in a large number of test sentences. Prepositions were found impaired in both Broca’s and anomic aphasia. Most of the parameters could not account for the data, and some data were in the opposite direction to the predicted. No disproportionate impairments of meaningless prepositions were found and prepositions with syntactic function were best preserved in the majority of patients. Patients made predominately within-category substitution errors. The results are interpreted as evidence for preserved syntactic knowledge about prepositions. It is suggested that a deficit at the post syntactic level of (late) spell-out is the underlying reason for the preposition deficit.
from the Journal of Neurolinguistics
Grammatical morpheme effects on sentence processing by school-aged adolescents with specific language impairment
Sixteen-year-olds with specific language impairment (SLI), nonspecific language impairment (NLI), and those showing typical language development (TD) responded to target words in sentences that were either grammatical or contained a grammatical error immediately before the target word. The TD participants showed the expected slower response times (RTs) when errors preceded the target word, regardless of error type. The SLI and NLI groups also showed the expected slowing, except when the error type involved the omission of a tense/agreement inflection. This response pattern mirrored an early developmental period of alternating between using and omitting tense/agreement inflections that is characteristic of SLI and NLI. The findings could not be readily attributed to factors such as insensitivity to omissions in general or insensitivity to the particular phonetic forms used to mark tense/agreement. The observed response pattern may represent continued difficulty with tense/agreement morphology that persists in subtle form into adolescence.
Conclusions: The results provide strong support for the role of phonological complexity in explaining some of the variability in children’s production of 3rd person singular -s. This suggests that future research will need to consider multiple factors, including phonological and positional effects, in constructing a comprehensive developmental theory of both grammatical competence and processes of speech planning and production.