Mean length of utterance (or MLU) is a measure of linguistic productivity in children. It is traditionally calculated by collecting 100 utterances spoken by a child and dividing the number of morphemes
Morpheme
In linguistics, a morpheme is the smallest grammatical unit in a language. In other words, it is the smallest meaningful unit of a language. The field of study dedicated to morphemes is called morphology. A morpheme is not identical to a word, and the principal difference between the two is that a morpheme may or may not stand alone, whereas a word, by definition, is freestanding.
What is MLU and how is it calculated?
It is traditionally calculated by collecting 100 utterances spoken by a child and dividing the number of morphemes by the number of utterances. A higher MLU is taken to indicate a higher level of language proficiency.
Should MLU be measured in words or morphemes?
An additional issue concerns whether MLU should be measured in words (MLU-w) or morphemes (MLU-m), the latter option being the most difficult to gauge, since new challenges have arisen regarding how to count zero morphemes, suppletive and fused morphemes.
What is the difference between MLU-W and mlu3-m?
In contrast, measuring utterance length in MLU-w or MLU-m in a language with predominantly monomorphemic words like English (3a', 3b', 3c') does not make much difference: MLU3-w: 12/3 = 4; MLU3-m = 13/3 = 4.33. MLU3-w and MLU3-m calculations were performed by two independent coders.
What is MLU in early childhood education?
MLU is short for mean length of utterance. Mean length of utterance is the average number of morphemes per utterance. MLU is used as a benchmark to assess individual differences and developmental changes in grammatical development in children in the early stages of language acquisition.
What does mean length of utterance mean?
When we talk about increasing sentence length in children, we often use the term “mean length of utterance”. This refers to the average length of the sentences that a child typically uses.
How is MLU speech therapy calculated?
One you have a document with just the child's utterances, go to Tools —> Word Count. Step Three: Divide the number next to Words (113 in this example) by 50 (the total number of utterances). This calculation gives you an MLU of 2.26.
What is MLU in speech therapy?
Mean Length of Utterance (MLU) reflects the average sentence length in words for a language sample. Mean Clauses per Utterance (MCU) obtained by identifying each main and embedded or subordinate clause and determining the average number of clauses per utterance for the entire language sample.
What can MLU tell you about a child's language skills?
We can conclude, then, that an MLU of 4.25 would be expected in a child of between 45-48 months of age. As we know that our particular child is 48 months old, then it appears that the average length of the child's utterances is age appropriate....Age equivalent.MLUage equivalent (within 1 month)5.02545.32575.636011 more rows•Jan 29, 2014
Why is mean length of utterance important?
Mean length of utterance is a good marker of language impairment. It is the number of words or morphemes in each of their spontaneous utterances. It can be used to benchmark language acquisition and is used to compare language intervention outcomes in children with autism.
Why is language sampling important?
Language samples provide some of the most useful information we can gather about a child's communication because it's an immediate snapshot of: Utterance length. Complexity. Articulation abilities.
What is normal MLU?
MLU Norms. Thanks again to Roger Brown, we know what to expect of a typically developing child with regard to their utterance length at different ages: 12-26 months: average MLU is 1.75 morphemes, with a range from 1.0 to 2.0. 27-30 months: average MLU is 2.25, with a range from 2.0 to 2.5.
How do you analyze a speech sample?
The Most Important Thing to Analyze: The Speech ObjectivesWhat is the speaker's goal? Is it to educate, to motivate, to persuade, or to entertain?What is the primary message being delivered?Why is this person delivering this speech? Are they the right person?Was the objective achieved?
How do you calculate the number of utterances?
How to Measure Mean Length UtteranceWrite down 50 to 100 phrases or sentences that a child says. ... Count the morphemes in each sentence. ... Add the morphemes from each phrase and divide by the total number of phrases. ... Compare the child's average length of utterance with data for his age level.
Does MLU measure morphology?
MLU, DSS, and IPSyn are three measures of morphology and syntax in speech samples which are valid for English-language studies. Various researchers show that the total score of DSS and IPSyn are appropriate scales for morpho-syntactic structures.
Is MLU syntax or morphology?
Mean Length Utterance (MLU) is a quantitative measure for morpho-syntactic complexity. It indicates how many morphemes or words a child uses per utterance. In other words: a higher value of the MLU means that a child is capable of producing more complex sentences.
How do you increase mean length of utterance speech therapy?
One intervention that has been used to increase MLU is expansion. Expansion is when an adult responds to a child's utterance by expanding their sentence to form a more complete or complex sentence. This study used an Expansion Intervention to increase the MLU of preschool aged students.