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Assessing productivity and stimulability of tense and agreement morphemes in typically developing children and AAC speakers

Kovacs, Thomas (2018) Assessing productivity and stimulability of tense and agreement morphemes in typically developing children and AAC speakers. Doctoral Dissertation, University of Pittsburgh. (Unpublished)

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Expressive morphology skills are rarely assessed in children who use augmentative and alternative communication (AAC). Pediatric AAC speakers may therefore have undocumented difficulty acquiring morphemes in the English tense and agreement system. Optional infinitive (OI) theory and gradual morphosyntactic learning (GML) theory predict different patterns of development within the tense and agreement system and different patterns of cross-morpheme generalization. This dissertation tested these competing hypotheses and used theoretically driven tasks to assess the tense and agreement systems of typically developing children and pediatric AAC speakers with cerebral palsy.
Experiment 1: Play-based language samples were collected from typically developing 30-54 month olds. Tense and agreement morpheme use and productivity were measured in samples of 150 multi-morpheme utterances. Tense marker totals and productivity scores increased with age. Morpheme category productivity grew at different rates in different categories, which was most consistent with predictions of GML theory. COPULA BE productivity was at ceiling. -3s, -ed, and AUXILIARY DO productivity were all significantly higher than AUXILIARY BE productivity. An unexpected divergence between -3s and -ed productivity was not consistent with either theory.
Experiment 2: Tense and agreement morpheme stimulability was assessed in the children from Experiment 1. Communication modality (spoken or graphic symbol) was randomly assigned. No significant age-by-communication modality interactions were found. When significant main effects of age were found, stimulability increased with age. When significant main effects of communication modality were found, stimulability was higher in the spoken modality. Morpheme category stimulability grew at similar rates across categories, which was consistent with predictions of OI theory.
Experiment 3: Pretest tense marker use, productivity, and stimulability were assessed in pediatric AAC speakers. A target tense marker that was stimulable and not used in the pretest assessment was identified for each participant. A short course of intervention focused on production of the target tense marker and copula is. Both participants used target tense markers and copula is more productively in a posttest assessment. Possible cross-morpheme generalization was found for tense markers that shared grammatical features with the target or copula is. This was most consistent with predictions of GML theory.


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Item Type: University of Pittsburgh ETD
Status: Unpublished
CreatorsEmailPitt UsernameORCID
Kovacs, ThomasTRK30@Pitt.eduTRK30
ETD Committee:
TitleMemberEmail AddressPitt UsernameORCID
Thesis AdvisorHill, KatyaKHill@Pitt.eduKhill
Committee MemberDickey, Michael WalshMDickey@Pitt.eduMDickey
Committee MemberYaruss, J.
Committee MemberNyberg,
Date: 10 January 2018
Date Type: Publication
Defense Date: 1 November 2017
Approval Date: 10 January 2018
Submission Date: 29 November 2017
Access Restriction: No restriction; Release the ETD for access worldwide immediately.
Number of Pages: 263
Institution: University of Pittsburgh
Schools and Programs: School of Health and Rehabilitation Sciences > Communication Science and Disorders
Degree: PhD - Doctor of Philosophy
Thesis Type: Doctoral Dissertation
Refereed: Yes
Uncontrolled Keywords: augmentative and alternative communication, language development, language acquisition, assessment, morphosyntax, tense marking, productivity, stimulability, language sample analysis
Date Deposited: 10 Jan 2018 15:11
Last Modified: 10 Jan 2018 15:11


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