Mean Length of Utterance Levels in 6-Month Intervals for Children 3 to 9 Years With and Without Language Impairments

Abstract

Purpose The mean length of children’s utterances is a valuable estimate of their early language acquisition. The available normative data lacks documentation of language and nonverbal intelligence levels of the samples. This study reports age-referenced MLU data from children with specific language impairment and children without language impairments. Method 306 child participants were drawn from a data archive, ages 2;6–9;0 years, 170 with SLI and 136 control children. 1564 spontaneous language samples were collected, transcribed and analyzed for sample size and MLU in words and morphemes. Means, standard deviations, and effect sizes for group differences are reported for MLUs, along with concurrent language and nonverbal intelligence assessments, per 6-month intervals. Results The results document an age progression in MLU words and morphemes, and a persistent lower level of performance for children with SLI. Conclusions The results support the reliability and validity of MLU as an index of normative language acquisition and a marker of language impairment. The findings can be used for clinical benchmarking of deficits and language intervention outcomes, as well as comparisons across research samples.

Standardized Versus Naturalized: An Evaluation of Child Morphological and Syntactic Assessments

“…Thus, language sampling may be more indicative of a child's true morphosyntactic abilities than standardized results for younger children; however, both language sampling and the CELF-P 2 may provide valid morphosynactic results for older children. The findings are congruent with Rice et al (2010) who established age-referenced MLU as a reliable and valid measurement of language acquisition. Akin to the present study, Rice et al (2010) documented that MLU increased with age progression.…”

“…The findings are congruent with Rice et al (2010) who established age-referenced MLU as a reliable and valid measurement of language acquisition. Akin to the present study, Rice et al (2010) documented that MLU increased with age progression.…”

“…Five out of six participants (83%) had MLU AEs representative of their chronological ages (CA) (see Table 1). Age-equivalence scores were reported as a reliable and age-validated measure of syntactic growth in children with and without SLI (Rice et al, 2010). Results of that study conducted by Rice et al (2010) revealed MLU calculation is sensitive to language impairment throughout the range for which MLU is considered a reliable index.…”

“…MLU, as defined by Rice et al (2010), is the number of morphemes, or the units of meaning, in each of a young child's natural utterances. Brown's grammatical morphemes appear throughout a young child's life and help shape the meaning of the child's utterances.…”

“…Rice et al (2010) compared MLU to age-referenced normative data for typically developing children and children with specific language impairment (SLI) (ages 2.6-9.0). A correlation between age progression and MLU was revealed, suggesting that MLU yields reliable and valid results of children's language acquisition in comparison to age (Rice et al, 2010).…”