Ta’lim sohasi: 110000 Pedagogika Ta’lim yo`nalishi

Root-morphemes are the semantic centre of the words and the basic constituent part without which the word is inconceivable.

Non-root morphemes include grammatical morphemes (inflections) and derivational morphemes (affixes).

Inflections carry only grammatical meaning reflecting grammatical categories (tense, number, person, degree, etc.).

Affixes are relevant for building various types of stems – the part of a word that remains unchanged throughout its paradigm. Lexicology is concerned only with affixational morphemes, but not with inflectional ones, unless they are important for word building.
Affixes are classified into prefixes and suffixes: a prefix precedes the root-morpheme, a suffix follows it. Besides, we also distinguish infixes (a few) and semi-affixes.
A free morpheme coincides with the stem or a word-form. A great many root-morphemes are free morphemes, for example, the root-morpheme friend of the noun friendship is naturally qualified as a free morpheme because it coincides with the noun friend.
A bound morpheme occurs only as a constituent part of a word. Affixes are, naturally, bound morphemes, for they always make a part of a word, e.g. the suffixes -ness, -ship, -ise (-ize), etc., the prefixes un-, dis-, de-, etc. (e.g. readiness, comradeship, to activise; unnatural, to displease) and can not be used separately.

Semi-bound (semi-free) morphemes are morphemes that can function in a morphemic sequence both as an affix and as a free morpheme (a word). For example, the morpheme well and half, on the one hand, occur as free morphemes that coincide with the stem and the word-form in utterances like sleep well, half an hour, on the other hand, they occur as bound morphemes in words like well-known, half-eaten, half-done.
The procedure generally employed for the purposes of segmenting words into the constituent morphemes is the method of Immediate and Ultimate Constituents. During breaking a word into its constituents at each stage of the procedure we segment the word into immediately broken morphemes, and they are termed as the Immediate Constituents (ICs). We finish the process of segmentation when we arrive at constituents which cannot be further broken, and these indivisible morphemes are referred to as the Ultimate Constituents (UCs).
The nature, type and arrangement of the ICs of the word is known as its derivative structure.
According to the derivative structure all words fall into such classes: simplexes (simple), non-derived words and complexes (derivatives).