Language DevelopmentLecture Notes: 9/30/14Vocabulary Spurt● Also known as the word spurt, word explosion, naming explosion● Lexical development starts slowly (takes a year to get to the 50-word mark; 8-11 words acquired per month)● At the 50 word mark (around 18 months) = sudden shift● Word-learning rate increases to 22-37 words/month, and new words get learned only after a single exposureWhy would vocabulary spurt occur?● Explanation 1: There is an internal “word-learning” mechanism that gets “turned-on”● Explanation 2: 50 words is what a child needs to figure out how the lexicon works○ I.e., it is enough to get the “naming insight” = realization that everything has a name○ I.e., it is enough to start using the mutual-exclusivity constraint (the more words you know, the more you will assume that new words apply to new things)● Explanation 3: Ongoing cognitive development○ Understanding that objects can be grouped into categories occurs at about the same time as the naming spurtExplanation #4: “Nothing is Happening”● A few words are easy to learn, a few are difficult, but most lie in between● Babies are exposed to many words each day, through direct conversation and hearing speech around them● Each exposure to a word imparts some information about its sound or meaning● Words are learned in parallel. That is, children can build partial knowledge for many words at the same time. They don’t have to finish learning “mommy” in order to start learning “daddy”.● Easy words = less exposure needed, less time to learn needed● More difficult words = more exposure needed, more time to learn needed● Result: Multiple exposures to more difficult words until hit a point where they result in learning. Development of the Semantic-Lexical Networks● The more words the child knows, the more difficult it is to store all of them on an individual basis● Vocabulary system is organized around commonalities between words A Shift in Vocabulary Organization● Growth of semantic networks organized around similarities in meaning is obvious at around 7 years of age● Syntagmatic-Paradigmantic Shift○ Word-Association Task■ Prior to age 7: responses to cues are related syntagmatically (i.e., through syntax).● Eat-ice cream■ After age 7: responses to cues are related paradigmatically (i.e., through meaning)● Eat-drinkHow do children learn words?● One of the challenges: extending the word to multiple objects in the same category● Solution: concepts are innate, and children just map the word onto all the instantiations of the concept● Example: Concept of space is innate. All children have to do is map labels onto spatial learningBut..different languages carve up space differently● If conceptual categories are innate, or learned before language, then these differences should not matter○ All children, independent of language, should have the same spatial categories● If, however, conceptual categories are influenced by language, then:○ Children raised with different languages should talk about space differentlyEnglish vs. Korean● In English- put in vs. put on- difference between containment (in) and support (on); independent of whether tight or loose fit○ I.e., put cassette in the case and put apple in the bowl● In Korean- kkita vs nehta- difference between tight-fit (kkita) and loose fit (nehta); independence of whether containment or support○ I.e., cassette in the case = kkita, but apple in the bowl = nehta● What counts as containment must be learned in each language. Pure perception is not enough.Do English and Korean children talk about space differently?● First spatial words are language-specific○ English children focused on containment (in; out) and support (on; off)○ Korean children focused on tight-fit and loose-fit. No distinction between containment and support ● 18-23 month old children comprehend spatial terms in language-specific ways○ English children preferred to look at containment when hearing “in”: Korean children preferred to look at tight-fit when hearing