One of the issues in infants’ language acquisition is - how do infants find
word-like forms from fluent speech. Previous literature on infants word segmentation
has mostly focused on understanding the bottom-up cues, i.e., cues
in the input such as acoustic/prosodic cues, that infants utilize in pulling out
nouns. This dissertation asks whether infants can use top-down cues in pulling
out verbs. Verb segmentation has been reported to be delayed as compared to
noun segmentation and these results have been used to explain the delay in its
acquisition of verbs. This dissertation argues otherwise, demonstrating that in
fact at the beginning of word segmentation, i.e., at 6-months, infants can pull
out verbs with the help of a known word mommy (a paradigm used in Bortfeld,
Morgan, Golinkoff, & Rathbun, 2005).
The current dissertation goes further and asks how these verbs are represented.
To be specific, this dissertation looks at 6-month-olds’ segmentation of
morphologically complex verbs, such as walking, walks, and walked, and asks
whether preverbal infants can relate these forms to the root form walk. The
main focus of this research is to understand how prelexical infants, who cannot
rely on semantics, relate complex forms to the root forms.
This dissertation expands our understanding of the role of the functional
morphemes (such as -ing, -ed, -s) in this process by conducting a corpus analysis
as well as behavioral experiments. In this dissertation, I locate the beginning
stage of this complex form acquisition and show that at 6-months, infants start
segmenting complex verbs, and based on the frequency and the characteristics
of the functional morphemes, infants begin to relate complex forms to root
forms. The findings of this dissertation highlight the importance of top-down
cues in early language development and have crucial implications for verb acquisition.
Also, these results provide evidence for morpheme-based processing
models and acquisition models such as prosody-functor models, arguing for
early representation of functional elements and their facilitatory influence on
word segmentation and representation.
