Dissertations, Theses, and Capstone Projects

Date of Degree


Document Type


Degree Name



Speech-Language-Hearing Sciences


Michelle MacRoy-Higgins

Committee Members

Valerie Shafer

Isabelle Barriere

Subject Categories

Speech and Hearing Science | Speech Pathology and Audiology


expressive language delay; lexical diversity; morphology; social-pragmatic language; attention allocation; mother-child dyad play


Late talkers (LT) are two-year-old children with expressive language delays, who do not yet have a lexicon of fifty words, and do not combine words. Maternal child-directed language to these children, termed ‘maternal input’ may influence their language learning. The first aim of this study was to examine the relationship between a child’s language, as measured by expressive vocabulary, and the child-directed speech by the mother of the child. Maternal input to late-talking children was compared to the maternal input presented to two typical language matched groups: an age-matched group of children (AM) and a vocabulary-matched group of children (VM) with typical language development. The second aim of the study was to examine the attention allocation of the LT children to the toy objects during the same play interaction, when compared to the attention allocation of the AM children with typical language development (TLD).

Twenty-seven monolingual English-speaking mother-child dyads participated in the study; all dyads were part of a homogenous socioeconomic status (SES) group. Nine mother-child dyads included LT children, while nine mother-child dyads included AM children and nine other mother-child dyads included VM children. An eight-minute play interaction between each mother-child dyad was recorded and analyzed to determine the following maternal input measures: lexical diversity (total number of utterances, word tokens, and word types), morphology (mean length of utterance, bound morphemes) and social-pragmatic language properties (questions, directives). Similarities in maternal input to the three participant groups included: number of total utterances, word tokens, word types, number of other questions, and number of strong, joint, and attentional directives. Differences in maternal input were found in the AM participants. Mothers of AM children produced significantly higher MLU, more bound morphemes, a higher percentage of bound morphemes, and more wh-questions in their input than mothers’ input to the LT participants. These findings suggest that mothers of AM children may be providing richer and more complex language to their children during play.

Attention allocation skills of young children is another factor known to modulate language learning. Attentional focus plays an important role in language acquisition, as attention has been correlated with word learning in typically developing children and those who are late talkers. Therefore, the second aim of this study was to examine the attention allocation of the LT participants to the toy objects during the same eight-minute mother-child dyad play interaction when compared to the attention allocation of age-matched children with typical language development (AM). Attention allocation was measured using duration examining of the objects in play, specifically the duration of time, in seconds, in which children were attending to, examining, and manipulating toys.

No differences were found in the presence of attention allocation between the LT and AM groups during play, indicating that the two groups of children displayed a similar amount of time of focused attention and examination/manipulation of objects during mother-child dyad play. However, the LT group had a significantly longer duration of time in seconds engaged in episodes of inattention, indicating a greater amount of time in which the LT children did not look at or attend to the toys, nor did they examine or manipulate toys in play, when compared to the AM children. This finding may suggest that the reduced attention of LT children to toys when compared to AM children may affect word learning during maternal input in mother-child play. Further investigation is necessary to better understand the relationship between input, attention, and language development.