1. Record enough natural speech to yield at least one hundred consecutive
utterances after stages 2 to 3 below.
2. Transcribe the speech.
all utterances where it is unclear what the child said.
exclamations, mm, oh, etc, except when they form the entire utterance
false starts, want - want drink
4. Count the number of morphemes, both content and grammatical, counting
as a single morpheme:
compound words, choo-choo, birthday etc
words with ie/y, mummy, doggie
irregular past tense, went
but including as separate morphemes:
· auxiliaries; will, , is, s, have, ve, etc
· all inflected endings -s, -ed, etc
5. Divide the total by the number of utterance to get the MLU in morphemes.
L1 sources: Roger Brown, Paul Fletcher