• MLU – mean length of utterance – Roger brown 1969
Total number of morphemes
Number of utterances
Stage 1 – 1.1 – 2.0
Stage 2 – 2.0 – 2.5
Stage 3 – 2.5 – 3.0
Stage 4 – 3.0 – 3.5
Stage 5 – 3.5-4.0
Theories and the ages at which they are applicable:
• Pre-linguistic (phonology) – 0-1 years
• Brown’s MLU theory – 1-4+ years
• Halliday’s Taxonomy – 9 months – 4+ years
• Vocabulary (e.g Katherine Nelson – learning what words do) – 6 months – 4+ years
• One/two word/telegraphic etc (Crystal 1976) – 10 months – 4+ years
• Negatives (Ursula Bellugi 1967) – 2-4+ years
• Asking questions (Clarke 1985) – 1-4+ years
How is language development studied?
• Naturalistic observation = recording children speaking in natural circumstances
• Controlled experiment = controlling the interview situation by asking pre-planned questions or getting the child to play a game.
How do children learn to speak so well in such a short time?
1. All children learn to speak within a few years unless brain damaged.
2. Very few parents are trained to accomplish this task.
3. Babies are given no or little explicit instruction to help them.
4. Babies hear only a limited sample of language whilst they learn it.
5. Babies produce sentences they have never heard anyone say.
6. Few other animals are capable of much language at all.
7. There are no gaps in between words in spoken language: babies hear a continuous stream of sound.
8. If you expose a baby to two languages at the same time they will learn both.
By Heather
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