Grammar as a phenomenon – a subsystem of language as a linguistic discipline

Classes of Adjectives
According to their meaning and grammatical characteristics, adjectives can be classified into qualitative and relative. Qualitative adjectives denote qualities of a substance directly, e.g.: small, brown, quick, etc. Most qualitative adjectives have degrees of comparison, e.g.: small - smaller - smallest.
Degrees of Comparison
Linguistic Status of the Category of Degrees of Comparison
The problem of degrees of comparison has given rise to much controversy. First of all, there is no unity of opinion concerning the character of this category in Modern English. Some linguists think that degrees of comparison should be treated as a lexical category. In their opinion, long - longer - longest represent three different words, not forms of one and the same word.
Criticizing this point of view, А.1. Smirnitsky says that long-longer - longest are not different words, but forms of the same word because they have the same stem long and are consequently characterized by identical lexical meaning.

The category is constituted by the opposition of the three forms known under the heading of degrees of comparison; the basic form (positive degree), having no features of comparison; the comparative degree form, having the feature of restricted superiority (which limits the comparison to two elements only); the superlative degree form, having the feature of unrestricted superiority.

Synthetical and analytical forms
The synthetical forms of comparison in -er and -(e)st coexist with the analytical forms of comparison effected by the auxiliaries more and most. The analytical forms of comparison perform a double function. On the one hand, they are used with the evaluative adjectives that, due to their phonemic structure (two-syllable words with the stress on the first syllable ending in other grapho-phonemic complexes than -er, -y, -le, -ow or words of more than two-syllable composition) cannot normally take the synthetical forms of comparison. In this respect, the analytical comparison forms are in categorial complementary distribution with the synthetical comparison forms. On the other hand, the analytical forms of comparison, as different from the synthetical forms, are used to express emphasis, thus complementing the synthetical forms in the sphere of this important stylistic connotation. Cf.: The audience became more and more noisy, and soon the speaker's words were drowned in the general hum of voices.
Besides the already mentioned synthetic and analytical forms of degrees of comparison, there are irregular forms. A few adjectives have suppletive forms of comparison that are derived from different roots, e.g.: good - better - best, bad-worse - worst.