The words of language are divided into grammatically relevant sets of words are called traditionally parts of speech.
In modern linguistics parts of speech are descriminated on the basis of the three
criteria: semantic, formal and functional.
Parts of speech are classified into notional and functional parts of speech.
Notional parts of speech possess all three characteristics: functional, formal and
the main-semantic.
There are: the noun, the verb, the pronoun, the adjective, the
numeral, the adverb.
The functional parts of speech are words of incomplete
nominative meaning and non-self-dependent. The basis functional parts of
speech are^ the preposition, the article, the conjunction, the particle, the modal
words, the interjection.
The notional parts of speech each of them has peculiar semantic, formal and
functional features.Besides the notional parts of speech can be subcategorized on some semantic or
grammatical (formal and functional) criteria.
Thus the noun is usually divided into such subclasses as:
-proper and common;
-animate and inanimate;
-countable and uncountable
and some others.
Formal parts of speech preserve their homogyneous quality and are not
subjected to subcategorization