mean length of utterance
A quantitative measure of grammatical development calculated by dividing total morphemes by total utterances in a language sample.
Full Definition
Mean Length of Utterance (MLU) is a widely used metric for assessing grammatical complexity and language development, particularly in young children. Calculated by dividing the total number of morphemes by the total number of utterances in a representative language sample, MLU provides insight into a child's syntactic and morphological development. Speech-language pathologists use MLU to compare a child's performance to developmental norms, track progress over time, and establish appropriate intervention targets. While traditionally calculated using morphemes, some variations use words or syllables as the counting unit depending on the language and assessment purpose.
Usage
Usage note: Commonly abbreviated as MLU; specify whether calculated using morphemes or words.
In Context
- "The child's mean length of utterance was 3.2 morphemes, indicating delayed syntactic development." — Language assessment report
- "Therapy goals target increasing mean length of utterance through grammatical expansion techniques." — Treatment planning