/ Dictionary / Index M mean length of utterance: Meaning and Definition of Find definitions for: mean' length' of ut'terance Pronunciation: [key] the mean number of morphemes produced per sentence, used esp. as a measure of child language development. Abbr.: MLU Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. mean latitude mean life Related Content Daily Word Quiz: diligent Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language