Mean length of utterance in children with specific language impairment and in younger control children shows concurrent validity and stable and parallel growth trajectories.

PURPOSE Although mean length of utterance (MLU) is a useful benchmark in studies of children with specific language impairment (SLI), some empirical and interpretive issues are unresolved. The authors report on 2 studies examining, respectively, the concurrent validity and temporal stability of MLU equivalency between children with SLI and typically developing children. METHOD Study 1 used 124 archival conversational samples consisting of 39 children with SLI (age 5;0 [years;months]), 40 MLU-equivalent typically developing children (age 3;0), and 45 age-equivalent controls. Concurrent validity of MLU matches was examined by considering the correspondence between MLU and developmental sentence scoring (DSS), index of productive syntax (IPSyn), and MLU in words. Study 2 used 205 archival conversational samples, representing 5 years of longitudinal data collected on 20 children with SLI (from age 5;0) and 18 MLU matches (from age 3;0). Evaluation of growth dimensions within and across groups was carried out via growth-curve modeling. RESULTS In Study 1, high levels of correlation among the MLU, DSS, and IPSyn measures were observed. Differences between groups were not significant. In Study 2, temporal stability of MLU matches was robust over a 5 year period. CONCLUSIONS MLU appears to be a reliable and valid index of general language development and an appropriate grouping variable from age 3 to 10. The developmental stability of MLU matches is indicative of shared underlying growth mechanisms.

[1]  D. Sherman,et al.  Review of Goldman-Fristoe Test of Articulation. , 1970 .

[2]  M L Rice,et al.  Tense over time: the longitudinal course of tense acquisition in children with specific language impairment. , 1998, Journal of speech, language, and hearing research : JSLHR.

[3]  M. Rice Growth Models of Developmental Language Disorders , 2004 .

[4]  W. Gavin,et al.  Sample size effects on temporal reliability of language sample measures of preschool children. , 1996, Journal of speech and hearing research.

[5]  J. Petrosko Columbia Mental Maturity Scale: Third Edition, 1972. Bessie B. Burgemeister, Lucille Hollander Blum, and Irving Lorge , 1973 .

[6]  M. Rice,et al.  The use of syntactic cues in lexical acquisition by children with SLI. Specific Language Impairment. , 2000, Journal of speech, language, and hearing research : JSLHR.

[7]  L. McAllister,et al.  An investigation of the MLU-age relationship and predictors of MLU in 2- and 3-year-old Australian children , 1998 .

[8]  Tina Bennett-Kastor,et al.  Analyzing children's language: Methods and theories , 1988 .

[9]  Mary E. Hughes,et al.  Boston University Conference on Language Development , 1979 .

[10]  Jon F. Miller,et al.  Assessing language production in children , 1980 .

[11]  Laurence B Leonard,et al.  Grammatical morpheme effects on MLU: "the same can be less" revisited. , 2003, Journal of speech, language, and hearing research : JSLHR.

[12]  J. Rondal,et al.  Age-relation, reliability and grammatical validity of measures of utterance length , 1987, Journal of Child Language.

[13]  Catherine E. Snow,et al.  Predictors of MLU: semantic and morphological developments , 1996 .

[14]  J E Janosky,et al.  Maternal education and measures of early speech and language. , 1999, Journal of speech, language, and hearing research : JSLHR.

[15]  Helen Tager-Flusberg,et al.  The relation of utterance length to grammatical complexity in normal and language-disordered groups , 1991, Applied Psycholinguistics.

[16]  R S Chapman,et al.  The relation between age and mean length of utterance in morphemes. , 1981, Journal of speech and hearing research.

[17]  T. Klee,et al.  A comparison of the age-MLU relation in normal and specifically language-impaired preschool children. , 1989, The Journal of speech and hearing disorders.

[18]  R. Brown,et al.  A First Language , 1973 .

[19]  Shula Chiat Understanding children with language problems , 2000 .

[20]  J. Blake,et al.  Evaluating quantitative measures of grammatical complexity in spontaneous speech samples , 1993, Journal of Child Language.

[21]  J. Singer,et al.  Applied Longitudinal Data Analysis , 2003 .

[22]  K. Wexler,et al.  Toward tense as a clinical marker of specific language impairment in English-speaking children. , 1996, Journal of speech and hearing research.

[23]  Masking of pure tones by broad-band noise in cochlear-impaired listeners. , 1982, Journal of speech and hearing research.

[24]  M.M. Nice,et al.  Length of sentences as a criterion of a child’s progress in speech , 1925 .

[25]  J. Horohov A study of specific language impairment (SLI) in the context of non-standard dialect , 1999 .

[26]  Heather K. J. van der Lely,et al.  SLI in Children: Movement, Economy, and Deficits in the Computational-Syntactic System , 1998 .

[27]  Paul Fletcher,et al.  Utterance length and lexical diversity in Cantonese-speaking children with and without specific language impairment. , 2004, Journal of speech, language, and hearing research : JSLHR.

[28]  Conversations with children who are language impaired: asking questions. , 1993, Journal of speech and hearing research.

[29]  M. Rice,et al.  Grammatical tense deficits in children with SLI and nonspecific language impairment: relationships with nonverbal IQ over time. , 2004, Journal of speech, language, and hearing research : JSLHR.

[30]  Jane E. Roberts,et al.  Research on fragile X syndrome and autism: Implications for the study of genes, environments, and developmental language disorders , 2004 .

[31]  J. Johnston An alternate MLU calculation: magnitude and variability of effects. , 2001, Journal of speech, language, and hearing research : JSLHR.

[32]  The temporal reliability of Brown's mean length of utterance (MLU-M) measure with post-stage V Children. , 1982, Journal of speech and hearing research.

[33]  Jon F. Miller,et al.  Language Sample Analysis: The Wisconsin Guide. Bulletin 92424. , 1994 .

[34]  P. A. Villiers,et al.  A cross-sectional study of the acquisition of grammatical morphemes in child speech , 1973, Journal of psycholinguistic research.

[35]  Alan G. Kamhi,et al.  Syntactic and Semantic Aspects of the Utterances of Language-Impaired Children: The Same Can Be Less. , 1984 .

[36]  S. Warren,et al.  Developmental language disorders : from phenotypes to etiologies , 2004 .

[37]  J. Wyckoff,et al.  A reconsideration of the relation between age and mean utterance length. , 1986, Journal of speech and hearing research.

[38]  T. Klee,et al.  The relation between grammatical development and mean length of utterance in morphemes , 1985, Journal of Child Language.

[39]  M. C. Templin Certain language skills in children , 1957 .

[40]  Sarita Eisenberg,et al.  The Use of MLU for Identifying Language Impairment in Preschool Children: A Review , 2001 .

[41]  P. Menyuk,et al.  Variability in children's use of grammatical morphemes , 1992, Applied Psycholinguistics.

[42]  S. Conant The relationship between age and MLU in young children: a second look at Klee and Fitzgerald's data , 1987, Journal of Child Language.

[43]  K. Wexler,et al.  Acquisition of irregular past tense by children with specific language impairment. , 2000, Journal of speech, language, and hearing research : JSLHR.

[44]  H. Scarborough Index of Productive Syntax , 1990, Applied Psycholinguistics.

[45]  E. Plante,et al.  Language matches: Illuminating or confounding? , 1993 .

[46]  Irving Lorge,et al.  Columbia mental maturity scale , 1954 .