R. S. Ginzburg, S. S. Khidekel, G. Y. Knyazeva, A. A. Sankin a course in modern english

dis-, de-, etc. (e.g. readiness, comradeship, to activise; unnatural, to displease, to decipher).
Many root-morphemes also belong to the class of bound morphemes which always occur in morphemic sequences, i.e. in combinations with ‘ roots or affixes. All unique roots and pseudo-roots are-bound morphemes. Such are the root-morphemes theor- in theory, theoretical, etc., barbar-in barbarism, barbarian, etc., -ceive in conceive, perceive, etc.
Semi-bound (semi-free) morphemes¹ are morphemes that can function in a morphemic sequence both as an affix and as a free morpheme. 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 relationship between the two classifications of morphemes discussed above can be graphically presented in the following diagram:

Speaking of word-structure on the morphemic level two groups of morphemes should be specially mentioned.
To the first group belong morphemes of Greek and Latin origin often called combining forms, e.g. telephone, telegraph, phonoscope, microscope, etc. The morphemes tele-, graph-, scope-, micro-, phone- are characterised by a definite lexical meaning and peculiar stylistic reference: tele- means ‘far’, graph- means ‘writing’, scope — ’seeing’, micro- implies smallness, phone- means ’sound.’ Comparing words with tele- as their first constituent, such as telegraph, telephone, telegram one may conclude that tele- is a prefix and graph-, phone-, gram-are root-morphemes. On the other hand, words like phonograph, seismograph, autograph may create the impression that the second morpheme graph is a suffix and the first — a root-morpheme. This undoubtedly would lead to the absurd conclusion that words of this group contain no root-morpheme and are composed of a suffix and a prefix which runs counter to the fundamental principle of word-structure. Therefore, there is only one solution to this problem; these morphemes are all bound root-morphemes of a special kind and such words belong to words made up of bound roots. The fact that these morphemes do not possess the part-of-speech meaning typical of affixational morphemes evidences their status as roots.^2
1 The Russian term is относительно связанные (относительно свободные).
² See ‘Semasiology’, §§ 15, 16, p. 24, 25.
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The second group embraces morphemes occupying a kind of intermediate position, morphemes that are changing their class membership.
The root-morpheme man- found in numerous words like postman ['poustmэn], fisherman [fi∫эmэn], gentleman ['d3entlmэn] in comparison with the same root used in the words man-made ['mænmeid] and man-servant ['mæn,sэ:vэnt] is, as is well-known, pronounced, differently, the [æ] of the root-morpheme becomes [э] and sometimes disappears altogether. The phonetic reduction of the root vowel is obviously due to the decreasing semantic value of the morpheme and some linguists argue that in words like cabman, gentleman, chairman it is now felt as denoting an agent rather than a male adult, becoming synonymous with the agent suffix -er. However, we still recognise the identity of [man] in postman, cabman and [mæn] in man-made, man-servant. Abrasion has not yet completely disassociated the two, and we can hardly regard [man] as having completely lost the status of a root-morpheme. Besides it is impossible to say she is an Englishman (or a gentleman) and the lexical opposition of man and woman is still felt in most of these compounds (cf. though Madam Chairman in cases when a woman chairs a sitting and even all women are tradesmen). It follows from all this that the morpheme -man as the last component may be qualified as semi-free.