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.

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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.

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Determiners are associated with nouns. Determiners include, for example, the articles "a" and " the," prenominal determiners (e.g., this, that, these, those), pronouns (e.g., I, you, me, his, her), and anaphors or reflexives (e.g., myself, himself, themselves). Tense is associated with verbs.

Tense includes, for example, negation (e.g., is/is not and does/does not), future modal "will" (He will run), the regular past tense "-ed" (She painted the chairs), infinitival "to" (He likes to run), copular and auxiliary "be" (He is big. They are running), and third person singular "-s" (The boys can do it).

Complementizers include words such as that, if, and whether which serve to introduce and characterize complement clauses in several ways (They wondered if Mary would come). Also included are various operations involved in the formation of questions ( Is she coming? Where is she going?).

Earliest to develop are determiners and tense, with complementizers coming in somewhat later. Functional category forms are especially problematic for children with language disorders yet it is critical that they master these forms because they are necessary to the comprehension and production of sentences.

As the functional categories are acquired, the hierarchical nature of sentences emerges. While children in the early word combination stage may produce bare noun and verb phrases, these do not exist in adult English. In sentences generated by competent language users, all nouns combine or Merge with determiners and become determiner phrases (DP). This is true even if there is no overt or spoken determiner in a phrase (Poets write poems). Similarly, verbs combine or Merge with tense elements and become tense phrases (TP).

N V

The child's "Ball Roll" comes to be replaced by the adult

DP TP

" The ball is rolling." This developmental step generally does not proceed smoothly for children with language disorders.

So what does this mean when considering language intervention? Foremost, it seems abundantly clear that receptive language intervention should be a central component in the Individualized Education Program (IEPs) of children with language disorders. Assistive technology (AT) can deliver accessible receptive language intervention that can supplement the services provided by speech-language pathologists. Computer software such as Laureate's language assessment and intervention programs can provide research based vocabulary and syntax training. The curriculums in these programs have been developed based on linguistic theory and research.

Early intervention intended to develop a core lexicon during the one-word stage should not focus solely on teaching the phonological and semantic (sound and meaning) features of the lexical categories. Rather, intervention should also place considerable emphasis on illustrating the syntactic features of the word--i.e., the use of the functional categories in association with nouns and verbs in various syntactic settings. Instruction should also include multiple exemplars of sentences in canonical SVO word order to facilitate the proper triggering of the word order parameters. Laureate's First Words, First Verbs, and First Words II Sterling Editions train early developing nouns and verbs using these strategies. An expert system called Optimized Intervention(r) automatically delivers the curriculum in developmental order and individualizes instruction based on student responses. During instruction and feedback, words in training are always presented in the context of full sentences. By using full albeit short sentences, the system is providing multiple examples of appropriate parameter settings for English. Additionally, the sentences employed are designed to provide systematic receptive language input illustrating functional category forms associated with the lexical category of the nouns and verbs being trained. Once a student has moved past the basic training levels, each word is associated with a unique reinforcement animation that provides additional examples of the word in full sentences. This happens during reinforcement animation--a point when one would expect the student's attention to be most fully engaged.

If in the late one-word stage or early two-word stage assessment indicates that the child does not have the two-word order parameters set, then it is important to introduce intervention specifically designed to trigger those parameters. Laureate's Simple Sentence Structure Sterling Edition provides intervention specifically designed to set the two word order parameters.

As children enter the two-word stage an emphasis should be placed on training early developing determiner, tense, and preposition functional category forms. LanguageLinks[R]: Syntax Assessment & Intervention and its companion program Prepositions! provide training on these critical functional category forms. A research project conducted in the Medford public schools demonstrated that these programs were effective in improving the expressive grammar of children with language disorders.

While proven teaching strategies should provide the basis for instructional procedures, linguistic theory and research should guide the choice of content in language intervention programs. Research shows that language input is critical to the development of vocabulary and syntax. For children with language disorders, this input has to be carefully structured. Software can provide effective and efficient language intervention necessary for these children to master grammar and become better communicators.

For a complete list of references used for this article write to lapel@eparent.com.

MARY SWEIG WILSON, PHD (CCC-SLP) IS A FELLOW, AMERICAN SPEECH-LANGUAGE-HEARING ASSOCIATION, A PROFESSOR EMERITA, COMMUNICATION SCIENCES, AT THE UNIVERSITY OF VERMONT AND THE PRESIDENT OF LAUREATE LEARNING SYSTEMS, INC.