Children all over the world learning thousands of different languages do so in a very similar manner. Surprisingly, first words emerge, word combinations occur, and syntax is mastered at about the same very young age regardless of language or culture. The uniformity and rapidity of first language acquisition is possible because human infants are born with a biologically endowed language faculty (Universal Grammar) within the brain that drives the course of language development. Neurotypically developing children need only exposure to acquire language. While the use of language for communication depends upon interaction, grammar (vocabulary and syntax) is acquired through listening alone not interaction. Following is a brief overview of current linguistic theory highlighting a few aspects that are especially important when planning language intervention.
Linguists throughout the world are currently working within Chomsky's Principles and Parameters Theory and its Minimalist Program. In the theory, Universal Grammar consists of a set of universal principles and a small set of parameters that are unique to human language. Universal principles unite all languages. They don't have to be learned because they are part of the genetically endowed language faculty and consequently are known without language experience. Since all parameters have two possible settings, children do need language input to select the proper setting for their native language. A fixed set of parameters account for most of the syntactic variations among human languages. Two very understandable universal parameters are those that determine the word order in a language. In terms of word order in sentences, English follows a pattern of Subject-Verb-Object (SVO). This order is determined by two different parameters. One determines whether objects follow or precede a verb, and the other determines whether subjects precede or follow verbs. In English, objects follow verbs and subjects come before them. For example, in English we say "The boy hit the ball" where "the ball" is the object, "The boy" is the subject, and the verb "hit" is the Head of the phrase. These two parameters and their settings determine word order in all languages. Remarkably, research has established that these two parameters are set when neurotypically developing children are still in the one-word stage.
In the Minimalist model, the lexicon (the mental dictionary of lexical items or words with their linguistic properties) has taken on a greater role in the grammar than it had in earlier generative grammar theory. This is important to us insofar as intervention is concerned. The lexicon is learned which means that once we understand the nature of it, we can use intervention strategies to teach children with language disorders. Each representation of a word consists not only of phonological and semantic (sound and meaning) properties, but also syntactic features such as categorial membership (i.e., whether it is a noun, verb, preposition, etc.), inflectional behavior (e.g., how it is marked for number, person, and gender), and in the case of verbs, syntactic argument structure. (For example, run requires only one argument, a subject " The girl runs." Kiss requires two arguments, a subject and an object " The father kisses the baby." Give typically requires three arguments "The girl gives the baby a toy.") In other words, the Minimalist Program assumes that a complete lexical entry includes the specific roles a word can play in the structure of language and the appropriate form of that word in a given grammatical context.
The lexicon is divided into lexical and functional categories. The lexical category includes the familiar nouns, verbs, and adjectives. The functional category consists of the less familiar determiners, tense, and complementizers. Many linguists believe that prepositions also fall into the functional category.
Determiners are associated with nouns. …