I. What is language?
There are 3 areas of language: pragmatics, semantics, and syntax/morphology. Semantics is the study of words and the meaning of words. Examples are concepts, object function, categories, etc. Pragmatics is the practical application of language; the ability to comprehend language and communicate with others. Syntax is the application of grammatical rules in language. Examples are pronouns, word order, sentence structure, etc. Morphology is the study of the smalledt units of meaning in a language, for example the plural [s], and how these units affect word meaning.
II. What are the characteristics of a language disorder/ delay?
Children who do not develop language shills appropriately are language delayed or disordered. Causes for a language delay/ diorder include: hearing impairment, cognitive impairments, autism, physical handicap that prevents the child from interacting with their environment, and lack of stimulation. Often, there is no idenifiable cause for language disorder.
Children can have receptive language impairments, expressive language impairments or both. Language disorders are changeable; at different stages of development children have different demands on their language systems. Receptive language impairments mean that a child has difficulty understanding language. They may have limited vocabulary. They may not understand the meaning of word endings: that adding "s" makes a noun plural, or "s" indicates possession, or that an "ed" ending on a verb means that the action is past. They may have difficulty understanding nonverbal signals, like body language. They may not understand sarcasm, or indirect requests (e.g., "it's cold in here" can mean please close the window").
Expressive language impairments show up in how a child speaks. They may use only a few words in each sentence. They may leave off word endings, or the little words like "is" and "are". They may not know the names of many words. They may not always use language appropriately and appear to be rude by being too direct or blunt. They might not consider their partner's needs, using ambiguous referents (lots of "he", "she" and "it" when the subject has not been clearly identified), or changing topics abruptly.
Remember that receptive language is usually slightly ahead of expressive language. If a child is speaking in 2 word utterances, he/she is probably able to fully understand 3 word utterances.