Development of grammars

Grammars evolve through usage and also due to separations of the human population. With the advent of written representations, formal rules about language usage tend to appear also. Formal grammars are codifications of usage that are developed by repeated documentation over time, and by observation as well. As the rules become established and developed, the prescriptive concept of grammatical correctness can arise. This often creates a discrepancy between contemporary usage and that which has been accepted, over time, as being correct. Linguists tend to view prescriptive grammars as having little justification beyond their authors' aesthetic tastes, although style guides may give useful advice about standard language employment, based on descriptions of usage in contemporary writings of the same language. Linguistic prescriptions also form part of the explanation for variation in speech, particularly variation in the speech of an individual speaker (an explanation, for example, for why some people say, "I didn't do nothing"; some say, "I didn't do anything"; and some say one or the other depending on social context).

The formal study of grammar is an important part of education for children from a young age through advanced learning, though the rules taught in schools are not a "grammar" in the sense most linguists use the term, particularly as they are often prescriptive rather than descriptive.

Constructed languages (also called planned languages or conlangs) are more common in the modern day. Many have been designed to aid human communication (for example, naturalistic Interlingua, schematic Esperanto, and the highly logic-compatible artificial language Lojban). Each of these languages has its own grammar.

Syntax refers to linguistic structure above the word level (e.g. how sentences are formed)—though without taking into account intonation, which is the domain of phonology. Morphology, by contrast, refers to structure at and below the word level (e.g. how compound words are formed), but above the level of individual sounds, which, like intonation, are in the domain of phonology.[8] No clear line can be drawn, however, between syntax and morphology. Analytic languages use syntax to convey information that is encoded via inflection in synthetic languages. In other words, word order is not significant and morphology is highly significant in a purely synthetic language, whereas morphology is not significant and syntax is highly significant in an analytic language. Chinese and Afrikaans, for example, are highly analytic, and meaning is therefore very context-dependent. (Both do have some inflections, and have had more in the past; thus, they are becoming even less synthetic and more "purely" analytic over time.) Latin, which is highly synthetic, uses affixes and inflections to convey the same information that Chinese does with syntax. Because Latin words are quite (though not completely) self-contained, an intelligible Latin sentence can be made from elements that are placed in a largely arbitrary order. Latin has a complex affixation and simple syntax, while Chinese has the opposite.