Record enough natural speech to yield at least one hundred consecutive utterances after stages 2 to 3

Transcribe the speech.

Eliminate:
— 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

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

Divide the total by the number of utterance to get the MLU in morphemes