Ўзбекистон республикаси олий ва ўрта махсус таълим вазирлиги ўзбекистон давлат жаҳон тиллари университети инглиз тили назарий аспектлари №1

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.