The investigation of morphology and lexical semantics is an investigation into the very essence of the semantics of word formation: the meaning of morphemes and how they can be combined to form meanings of complex words. Discussion of this question within the scholarly literature has been dependent on (i) the adopted morphological model (morpheme-based or word-based); and (ii) the adopted theoretical paradigm (such as formal/generativist accounts vs. construction-based approaches)—which also determined what problem areas received attention in the first place. One particular problem area that has surfaced most consistently within the literature (irrespective of the adopted morphological model or theoretical paradigm) is the so-called semantic mismatch question, which also serves as the focus of the present chapter. In essence, semantic mismatch pertains to the question of why there is no one-to-one correspondence between form and meaning in word formation. In other words, it is very frequently not possible out of context to give a precise account of what the meaning of a newly coined word might be based simply on the constituents that the word originates from. The article considers the extent to which the meaning of complex words is (at least partly) based on nondecompositional knowledge, implying that the meaning-bearing feature of morphemes might in fact be a graded affair. Thus, depending on the entrenchment and strength of the interrelations among sets of words, the meaning of the components contributes only more or less to a meaning of a word, suggesting that “mismatches” might be neither unusual nor uncommon.
Construction Morphology is a theory of word structure in which the complex words of a language are analyzed as constructions, that is, systematic pairings of form and meaning. These pairings are analyzed within a Tripartite Parallel Architecture conception of grammar. This presupposes a word-based approach to the analysis of morphological structure and a strong dependence on paradigmatic relations between words. The lexicon contains both words and the constructional schemas they are instantiations of. Words and schemas are organized in a hierarchical network, with intermediate layers of subschemas. These schemas have a motivating function with respect to existing complex words and specify how new complex words can be formed. The consequence of this view of morphology is that there is no sharp boundary between lexicon and grammar. In addition, the use of morphological patterns may also depend on specific syntactic constructions (construction-dependent morphology). This theory of lexical relatedness also provides insight into language change such as the use of obsolete case markers as markers of specific constructions, the change of words into affixes, and the debonding of word constituents into independent words. Studies of language acquisition and word processing confirm this view of the lexicon and the nature of lexical knowledge. Construction Morphology is also well equipped for dealing with inflection and the relationships between the cells of inflectional paradigms, because it can express how morphological schemas are related paradigmatically.
Analogy is traditionally regarded as one of the three main factors responsible for language change, along with sound change and borrowing. Whereas sound change is understood to be phonetically motivated and blind to structural patterns and semantic and functional relationships, analogy is licensed precisely by those patterns and relationships. In the Neogrammarian tradition, analogical change is regarded, at least largely, as a by-product of the normal operation (acquisition, representation, and use) of the mental grammar. Historical linguists commonly use proportional equations of the form A : B = C : X to represent analogical innovations, where A, B, and C are (sets of) word forms known to the innovator, who solves for X by discerning a formal relationship between A and B and then deductively arriving at a form that is related to C in the same way that B is related to A. Along with the core type of analogical change captured by proportional equations, most historical linguists include a number of other phenomena under the analogy umbrella. Some of these, such as paradigm leveling—the reduction or elimination of stem alternations in paradigms—are arguably largely proportional, but others such as contamination and folk etymology seem to have less to do with the normal operation of the mental grammar and instead involve some kind of interference among the mental representations of phonetically or semantically similar forms. The Neogrammarian approach to analogical change has been criticized and challenged on a variety of grounds, and a number of important scholars use the term “analogy” in a rather different sense, to refer to the role that phonological and/or semantic similarity play in the influence that forms exert on each other.