Language Development in the Child: Vocabulary

Language Development in the Child: Vocabulary (20-Oct-2003)

Newborn babies prefer the sound of their native language to others; presumably they've got used to hearing the rhythm/intonation (vocal folds) whilst in the womb [Trask]
babbling starts around 6 months; initially made up from all sorts of sounds, it develops to include the sounds of the native language. French mothers can identify French babbling, etc.. [Trask]
between 10-20 months, one-word stage; vocabulary builds slowly, one word at a time, but has no grammatical constructs [Trask].
very wide ranging, nouns, verbs, social ("hello"). It doesn't seem that children just learn one type of thing at a time and then move on to the next
contain words for internal status "comfy", objects "ball", actions "wash", disappearance "gone", attributes "big".
nouns dominate - seem to be the most easy thing for children to use (also easy for linguists to analyse)

underextension - children being more specific than necessary, e.g. "shoe" is only a shoe if it's a particular colour. Hard to spot (because it's not an obvious error) and therefore only studied relatively recently.
overextension - children overextend, or overgeneralise, so "shoe" may be applied to any foot covering. Quite easy to spot this happening.
overextension starts to narrow down after acquiring around 100 words [Fromkin]
Appears that to start with, children under-extend, and then over-extend
mismatch is when the child has a private meaning for a word, but this is very rare

Children learn 50 words within about 6 months of starting to talk
not clear that the child is using words as a "noun" etc., because there's no grammatical structure, so they're often classified e.g.
- specific nominal, e.g. "Adam"
- general nominal, e.g. "ball"
- personal social, e.g. "hi", "please"
- action, e.g. "wash"
one-word stage is sometimes referred to as "holophrastic" because the one word uttered conveys extra meaning than just the word - suggestion is that children have greater understanding than the vocabulary they possess allows them to express [Fromkin]

after a few months of two-word stage, "all hell breaks loose" (Pinker) - child start using many words, demonstrating knowledge of grammar, ability to construct complex sentences [Trask]
between ages of 2.5 and 3.5 "language explosion" [Fromkin]
between 18-24 months, two-word stage; e.g. "daddy car", "want juice". No three-word utterances, but some evidence of grammatical ability (may say "get ball" but won't say "ball get"). [Trask]
most of the new vocabulary consists of new object names - most sentences have one or two nouns in them, but it's easier to get away without verbs
coincides with first attempts to make proto-sentences, which are characterised by having lots of nouns, a bit like Washoe's conversation
earliest multiword utterances sometimes referred to as telegraphic speech - missing out linking words; e.g. "cathy build house" [Fromkin]. Maybe similar to texting - when communication under pressure, nouns are highly valued.
"spurt" results in about 8 new words acquired/day

Two ways to answer this: how much they talk, and how many different tokens they use. See chart from Crystal, e.g. at 1.5 years 14K words per day, using 2K different tokens.
vocabulary thought to be about 10,000 words by age 5 [Trask]

By age 20, vocabulary of 150K suggests you've learned about 20 words every day of your life, how can this be?
words come in sets (e.g. bird:robin, sparrow) so perhaps learning what "bird" makes it easier to learn different bird types
relational words - big, tall, fat, wide. So learning one may lay the foundation for learning the rest