Special Realizations of Morphemes: Zero-Morpheme
Either grammatical morphemes are free morphemes (also termed function words), e.g., in a text, mere particles as in the infinitive form to run, or grammatical morphemes are – as we have already seen -- bound inflectional morphemes normally attached to nouns to mark the plural form, tense, person or the comparative as in faster. The linguistic phenomena zero-morpheme violates such a neat, clear-cut definition and thus deserves to be analyzed in greater detail.
Within the field of inflectional morphology, the phenomenon of zero-affixation is unique; we have seen that complex words are usually formed by affixation to mark either tense, person, number, or case. Words may, however, also be formed without visibly modifying the structure of the input word that serves as the base. Take for instance the irregular verb to put and its past participle form put or the singular sheep and its plural realization sheep – in both cases, the inflectional morphemes as grammatical markers, representing concepts such as tense and number, are lacking any overt marking.
Along these lines, the notion of zero-affixation in inflectional morphology refers to those linguistic forms, which do not show up and are yet structurally given.