1 The main units of derivational analysis

asks, asked, asking is ask-; the stem of the word singer, singer's, singers, singers' 
is singer-. It is the stem of the word that takes the inflections which change the 
word grammatically as one or another part of speech. 
The structure of stems should be described in terms of IC's analysis, which 
at this level aims at establishing the patterns of typical derivational relations within 
the stem and the derivative correlation between stems of different types. 
There are three types of stems: simple, derived and compound. 
Simple stems are semantically non-motivated and do not constitute a pattern 
on analogy with which new stems may be modeled. Simple stems are generally 
monomorphic and phonetically identical with the root morpheme. The derivational 
structure of stems does not always coincide with the result of morphemic analysis. 
Comparison proves that not all morphemes relevant at the morphemic level are relevant at the derivational level of analysis.all types of pseudomorphemes are irrelevant to the derivational structure of stems as they do not meet requirementsof double opposition and derivational interrelations. So the stem of such words as retain, receive, horrible, pocket, 
motion, etc. should be regarded as simple, non- motivated stems. 
Derived stems are built on stems of various structures though which they are 
motivated, i.e. derived stems are understood on the basis of the derivative relations 
between their immediate constituents and the correlated stems. The derived stems 
are mostly polymorphic in which case the segmentation results only in one 
immediate constituents that is itself a stem, the other immediate constituent being 
necessarily a derivational affix³. 
Derived stems are not necessarily polymorphic. Compound stems are made 
up of two stems, both of which are themselves stems, for example. match-box, 
driving-suit, pen-holder, etc. It is built by joining of two stems, one of which is 
simple, the other derived. 
Bound lexical morphemes are affixes: prefixes (dis-), suffixes (-ish) and also 
blocked (unique) root morphemes (for example. Friday, cranberry). Bound 
grammatical morphemes are inflexions (endings), for example. -s for the plural of 
nouns, -ed for the Past Indefinite of regular verbs, -ing for the Present Participle, -
er for the comparative degree of adjectives. 
Derivationally all words form two structural classes: simple, or non-derived words and complex words or derivatives. Non-derived are words which cannot be segmented into ICs. Morphemically it may be monomorphic when its stem coincides with the free root-morpheme, e.g., hand, come, blue, etc., orpolymorphic when it is a sequence of bound morphemes, e.g., anxious, theory, public, etc. Derivatives are secondary, motivated units, made up as a rule of two ICs, e.g., friendliness, schoolmasterish, etc. The ICs are brought together according to specific rules of order and arrangement preconditioned by the system of the language. It follows that all derivatives are marked by the fixed order of their ICs.
The aim of derivational analysis is to study the nature, type and arrangement of the ICs of the word. In other words, the derivational analysis aims at establishing structural and semantic patterns words are built on, i.e. its derivative structure. Though the derivative structure of the word is closely connected with its morphemic structure and often coincides with it, it differs from it in principle.
The basic elementary units of the derivative structure of words are: derivational bases, derivational affixes and derivation patterns.
A derivational base is the part; of the word to which another base or an affix is added to make up a new word. Structurally derivational bases fall into three classes: 1) bases that coincide with morphological stems, e.g., duti/ful, dutiful/ly; day-dream, day-dream/er; 2) bases that coincide with word-forms, e.g., un/smiling, un/known; 3) bases the coincide with word-groups of different degrees of stability, e.g., second-rate/ness, flat-waist/ed, etc.
The first class, i.e. bases that coincide with morphological stems, make the largest group. Bases of this class are functionally and semantically distinct from all kinds of stems. Functionally, the morphological stem is the part of the word which is the starting point for its forms, the stem remains unchanged through its word-forms, e.g., filmstar (0), filmstar(s), filmstar('s), filmstar(s'). A derivational base is the starting point for different words, e.g. the nominal base hand gives rise to nouns (hand-bag, handwriting, shorthand), to adjectives (handy), verbs (to hand).
Derivational affixes possess two basic function⁴s: 1) stem-building which is common to all affixational morphemes: derivational and non-derivational. E.g., "ic-" in public, comic, music; 2) word-building which is the function of building a lexical unit of a structural and semantic type different from the one represented in the source unit, e.g., historic, economic, classic.