As Hannah and I talked today about some of the speech and language disorders that we have observed over the years, a particular point really caught my interest. Morphosyntax disorders (a subset of expressive language disorders) can manifest so differently in different children. We talked about some children we have known who had very similar language disorder presentations as one another, and other children, who also have language disorders but who seem share a different set of symptoms.
I'm writing this post in order to sort out my thoughts and hypothesize about some different classifications of morphosyntax disorders. I'll stick with describing children at about age four for ease of comparison.
Language disorder hypothesis: "Quiet Type"
At age four, these children play quietly. They have a short mean length of utterance (MLU) and low lexical variety (Type-Token Ratio; TTR). When they make grammatical mistakes they seem to be shortening and simplifying adult forms. Gestures and sound-effects replace some words when they are trying to get an important idea across even though they don't have the right word. When these children receive speech and language therapy, they are slow to learn specific conceptual or grammatical language targets, but they do make progress in overall communication.
Language disorder hypothesis: "Unmonitored Type"
At age four, these children are very talkative. They talk quickly and assume that you can understand them, even though you are having difficulty following their conversation. They have a typical MLU and typical lexical variety, but they make many grammatical deletions and substitutions that follow their idiosyncratic rules consistently. When these children receive speech and language therapy, they are quick to learn how to produce standard grammatical forms in structured activities, but have difficulty producing newly learned forms in conversation. When you point out an error, they sometimes know how to fix it, but at age four, they do not yet self-monitor or self-correct.
Language disorder hypothesis: "Memorizing Type"
I've talked about these children before in the post, Receptive Language Disorders and Memorization. At age four, these children love to recite scripts to themselves, and sometimes to other people. Their MLU is longer when you take into account their scripts, and shorter when you only measure creative utterances. Similarly, their grammar is more complex in their scripts, and less complex in their creative utterances. If they don't know what words or grammar to use, they use jargon to create their desired intonation patterns. They use few communicative gestures, although they often use scripted gestures to act out a memorized scene. When these children receive speech and language therapy, they are highly motivated to participate in language routines, but seem to get lost when you talk using regular child-directed language, because it is not predictable enough.
Language disorder hypothesis: "Quiet Type"
At age four, these children play quietly. They have a short mean length of utterance (MLU) and low lexical variety (Type-Token Ratio; TTR). When they make grammatical mistakes they seem to be shortening and simplifying adult forms. Gestures and sound-effects replace some words when they are trying to get an important idea across even though they don't have the right word. When these children receive speech and language therapy, they are slow to learn specific conceptual or grammatical language targets, but they do make progress in overall communication.
Language disorder hypothesis: "Unmonitored Type"
At age four, these children are very talkative. They talk quickly and assume that you can understand them, even though you are having difficulty following their conversation. They have a typical MLU and typical lexical variety, but they make many grammatical deletions and substitutions that follow their idiosyncratic rules consistently. When these children receive speech and language therapy, they are quick to learn how to produce standard grammatical forms in structured activities, but have difficulty producing newly learned forms in conversation. When you point out an error, they sometimes know how to fix it, but at age four, they do not yet self-monitor or self-correct.
Language disorder hypothesis: "Memorizing Type"
I've talked about these children before in the post, Receptive Language Disorders and Memorization. At age four, these children love to recite scripts to themselves, and sometimes to other people. Their MLU is longer when you take into account their scripts, and shorter when you only measure creative utterances. Similarly, their grammar is more complex in their scripts, and less complex in their creative utterances. If they don't know what words or grammar to use, they use jargon to create their desired intonation patterns. They use few communicative gestures, although they often use scripted gestures to act out a memorized scene. When these children receive speech and language therapy, they are highly motivated to participate in language routines, but seem to get lost when you talk using regular child-directed language, because it is not predictable enough.
These three categories don't capture every morphosyntax disorder. This is the first time I have tried to put this idea down on paper, so I know there are more types than just these three and the descriptions within these categories are just preliminary. I'll be thinking about this more.
