Vocabulary and Grammar in Young Children with Cochlear Implants and Typically Developing Children

Jongmin Jung, Purdue University


This study asked (1) whether young cochlear implant (CI) recipients have verb production and grammatical skills comparable to those of typically developing (TD) peers matched by spoken vocabulary size, and (2) whether there are associations between vocabulary variables (overall vocabulary size and verb vocabulary size) and grammatical measures. Additionally, three specific morphemes (i.e., articles, plural ‘s’ and third person singular ‘s’) were examined to answer whether the CI group had difficulty in using particular grammatical morphemes because of their perceptual limitations (i.e., challenges in perceiving stress pattern, and recognizing medial positioned morphemes). Young CI recipients (implanted before their third birthdays; n = 13) participated in the study. All the children had 24 months of CI experience, and had no other behavioral or cognitive disabilities. Thirteen typically developing (TD) children were matched with the CI group by their vocabulary size on the MacArthur Communicative Development Inventory (CDI). Verb vocabulary size was identified through parental report using the CDI. Four grammatical measures were identified from the CDI and language samples: (1) Grammatical Complexity, (2) Mean Length of Utterances (MLU), (3) Tense Marker Total (TMT) and (4) Productivity Scores (PS). Group comparison results showed that the two groups had comparable outcomes in verb vocabulary size and for all four grammatical measures. The CI group showed consistent associations between overall and verb vocabulary size and the four grammatical measures. In contrast, the TD group showed associations between vocabulary measures and only two grammatical measures: Grammatical Complexity and PS. In the examination of three specific morphemes, articles were more often omitted in the CI group than the TD group. Plural ‘s’ was comparably produced, but third person singular ‘s’ showed some vulnerability in the CI group. The findings of this study indicate that grammatical development of young CI recipients is strongly linked with their vocabulary size (overall and verb vocabulary size). These associations could result from specifically modulated language input for the CI users. The underlying factors that facilitate their language development need to be further examined.




Ertmer, Purdue University.

Subject Area

Speech therapy

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