Branches of linguistics. Synchronic vs diachronic approaches to the language study. Lexicology – ‘the science of the word’

Structural classification of morphemes:
free morphemes are morphemes which coincide with a word-form of an independently functioning word; they can be found only among roots, e.g. hero- as in heroism, event- as in eventful;
bound morphemes are morphemes which do not coincide with a separate word-form; they include all affixes, e.g. de- as in decode, -less as in fearless, -s as in girls; some root-morphemes, e.g. docu- as in document, horr- as in horrible, theor- as in theory etc;
semi-bound (semi-free) morphemes are morphemes which stand midway between a root and an affix; they can function as an independent full-meaning word and an affix at the same time, e.g. to speak ill of sb – to be ill-dressed / ill-bred / ill-fed;
Semi-prefixes: half-, mini-, midi-, maxi-, self-, by- etc.;
Semi-suffixes: -man, -like, -proof, -friendly, -oriented, -ware etc
Semantic classification of morphemes:
According to the role they play in the structure of words, morphemes fall into:
root (radical) morphemes – the lexical nuclei of words which are characterised by individual lexical meaning shared by no other morpheme of the language; the root remains after the removal of all functional and derivational affixes and does not admit any further analysis, e.g teach- in to teach, teacher, teaching;
non-root morphemes represented by inflectional morphemes (inflections) and affixational morphemes (affixes).
According to the position in a word, affixational morphemes fall into:
prefixes – derivational affixes standing before the stem and modifying its meaning, e.g. ex-minister, in-sensitive, re-read etc.; about 51 in the system of Modern English;