Collect a language sample of the utterances to be analyzed
Decide whether to count words or morphemes
Count the total number of words or morphemes in the sample
Count the total number of utterances in the sample
Divide the total number of words or morphemes by the total number of utterances
Use the formula: MLU = total words or morphemes ÷ total utterances
Report the result as the mean length of utterance in words or morphemes