Grammar in the systematic conception of language. The development of grammar and its types

Fusional languages
In Polish, noun declension collapses several factors into one ending: number (only plural is shown), gender, animacy, and case.
Morphemes in fusional languages are not readily distinguishable from the root or among themselves. Several grammatical bits of meaning may be fused into one affix. Morphemes may also be expressed by internal phonological changes in the root (i.e. morphophonology), such as consonant gradation and vowel gradation, or by suprasegmental features such as stress or tone, which are of course inseparable from the root.
The Indo-European and Semitic languages are the most typically cited examples of fusional languages. However, others have been described. For example, Navajo is sometimes categorized as a fusional language because its complex system of verbal affixes has become condensed and irregular enough that discerning individual morphemes is rarely possible. Some Uralic languages are described as fusional, particularly the Sami languages and Estonian. On the other hand, not all Indo-European languages are fusional; for example, Armenian and Persian are agglutinative, while English and Afrikaans lean more analytic.


Agglutinative languages
The term "grammar" goes back to a Greek word that may be translated as the "art of writing". But later this word acquired a much wider sense and came to embrace the whole study of language. Now it is often used as the synonym of linguistics. A question comes immediately to mind: what does this study involve?
Grammar may be practical and theoretical. The aim of practical grammar is the description of grammar rules that are necessary to understand and formulate sentences. The aim of theoretical grammar is to offer explanation for these rules. Generally speaking, theoretical grammar deals with the language as a functional system.
Most of the world’s languages belong to language families. A language family is a group of languages related by descent from a common ancestor, called the proto-language of that family. The major of that is Indo-European family. It is divided into several groups, which are also united genetically. One of them is Germanic group. English belongs to Germanic branch of Indo-European family. Indo-European languages are classified into two structural types –synthetic and analytic. Synthetic languages are defined as ones of “internal” grammar of the word. Here most of grammatical meanings and grammatical relations of words are expressed with the help of inflexions. Analytical languages are those of “external” grammar because most grammatical meanings and grammatical forms are expressed with the help of words (will do).
The basic concepts in the morphological classification of languages are
the morpheme and the word. The basic criteria for classification are the nature of the morphemes (lexical and grammatical) combined in a word; the method of their combination, such as pre- or post positioning of grammatical morphemes (which has a direct relation to syntax) and agglutination, or fusion (related to the field of morphophonemics); and the syntactically related connection between the morpheme and the word (such as isolation, when morpheme = word, or the analytic or synthetic character of word formation and inflection).
Morphological classification seeks to describe not specific languages (in which several morphological types are always present), but basic structural phenomena and trends in languages.
Morphological structure of languages is just one way of grouping languages.