Kids develop at different rates, and language-related delays are among the most common type of developmental delay, according to HealthyChildren.org. While some speech delays are temporary, some may indicate a more serious problem. To determine the linguistic productivity of a child, a pediatrician may suggest working with a speech language pathologist. The specialist may use what's called a "mean length of utterance" calculation to determine the child’s language proficiency.
When to Involve a Speech Language Pathologist
It is normal for kids to form sentences that sound strange, use incorrect grammar and misunderstand adults, according to speech language pathologist Caroline Bowen in the article “Typical Speech and Language Acquisition in Infants and Young Children.” However, it is not normal for a child to have little interest in communicating, stutter, have poor eye contact or only repeat what you say instead of forming her own sentences. It may be beneficial to have a speech language pathologist evaluate children who display such behaviors. Bowen states that a specialist can also help children who are tongue-tied, a condition known clinically as ankyloglossia; phonological disorders; hearing impairments; developmental disabilities; or any articulation disorder.
Morphemes and Utterances
To calculate a child’s utterances, a speech pathologist evaluates a child’s morphemes and utterances as he speaks. Every word has at least one morpheme, or meaning, according to the Josephine Chen Center for Speech and Language Pathology. For example, the word “play” has one meaning, or morpheme. The word “played” has two morphemes: the word “play” and the “-ed” at the end of the word, signifying the past tense. "Morphemes" relate to the individual words a child speaks, while "utterances" refer to the phrases he forms, including commands and phrases that don’t contain a link, or "copula" verb, as in: “The kitty mean to me.”
Words that Count as Morphemes
Words that speech pathologists count as morphemes when calculating utterances include diminutives, such as the word “kitty,” as well various kinds of verbs, according to Missouri State University. If a child stutters, the speech pathologist counts the word if the child completed it. If a word ends with “-ing,” “-ed,” “en” or “-s,” the inflection counts as a separate morpheme. Compound words like “see-saw” and “bye-bye” count as a single morpheme. Words that are contractions have two morphemes. A speech pathologist may not count a morpheme if a child repeats a word unnecessarily, makes an interjection or starts saying a word, but doesn’t continue.
Calculating a Child's Utterances
Speech pathologists use the "mean length of utterance" formula to calculate a child’s morphological development. To calculate, the specialist divides the total number of morphemes that a child spoke by the total number of utterances. The Josephine Chen Center for Speech and Language Pathology states that a healthy child’s mean length of utterance score is generally close to her age. It is common for a specialist to collect a sample of 100 utterances to calculate the score. Some specialists compare a child’s score to the stages of language development that psychologist Roger Brown identified in the book “A First Language: The Early Stages” to determine the development of her language skills. A child who has a low score for his age may have a language impairment, according to the U.S. National Library of Medicine.