Essentials for Speech
For human language to be possible, certain are necessary. These are physiological (the body must be of producing the sounds of speech), grammatical (the speech must have ); and semantic (the mind must be of dealing with the meanings of what is spoken).

Physiology
Although most of the human organs of speech to perform other (such as eating), they are so well for speaking that human speech appears to be the most efficient system of any living organism. In speech, an airstream is produced by the lungs and modulated by vibration (or lack of vibration) of the vocal cords and by movement of the tongue, the soft palate, and the lips. The airstream can be obstructed in degrees by the teeth and can be closed off from or kept open to the nasal cavity. People who have physiological impairments of speech and hearing still possess language, although the production and reception of language may have been to systems such as AMESLAN.

Grammar
All human language has a grammatical sound (signalling) units are combined to produce meaning. The units of sound combination that have meaning are called morphemes. A morpheme can to a word, but it can also refer to other sound combinations that have meaning but are not words (such as prefixes and suffixes). In the word coexist, for example, both co and exist are morphemes. Words and morphemes can be classed together according to what they do in a sentence. Classes of morphemes include parts of speech (such as nouns and verbs) as well as prefixes, suffixes, and so forth. Members of different word classes form phrases that in turn combine into larger units - sentences or utterances.

Semantics
, in human language, the speaker necessarily meaning to the sound , and the meaning is and understood by other humans who share the same language. The of meanings with sounds, words, and sentences and meanings that others in this way is believed to grammar as a tool for relating thoughts or ideas to speech, or signalling. Every meaningful sentence or utterance has a surface and an . At the surface are the words and sentence as spoken and . At the or deep level are the words and sentence as they are grammatically . This level of deep is where sentence appears . Two different surface can be to mean one thing, and one surface of a sentence may have two meanings. The surface sentence "Flying planes can be dangerous" means both that it can be dangerous for someone to fly planes and that planes that are flying can be dangerous. The different of this sentence have to do with its common surface having two deep structures. On the other hand, "To please John is easy" and "It is easy to please John", different surface , are the same sentence at the level of deep . Human is a combining special speech organs, grammatical , and intended and understood meanings.