In morphology, a null morpheme or zero morpheme is a morpheme that has no phonetic form. In simpler terms, a null morpheme is an "invisible" affix. It is a concept useful for analysis, by contrasting null morphemes with alternatives that do have some phonetic realization. The null morpheme is represented as either the figure zero (0) or the empty set symbol ∅.
In most languages, it is the affixes that are realized as null morphemes, indicating that the derived form does not differ from the stem. For example, plural form sheep can be analyzed as combination of sheep with added null affix for the plural. The process of adding a null affix is called null affixation, null derivation or zero derivation. The concept was first used by the 4th century BCE Sanskrit grammarian from ancient India, Pāṇini, in his Sanskrit grammar.
In English
Inflection
The existence of a null morpheme in a word can also be theorized by contrast with other forms of the same word showing alternative morphemes. For example, the singular number of English nouns is shown by a null morpheme that contrasts with the plural morpheme -s.
- cat = cat + -∅ = ROOT ("cat") + SINGULAR
- cats = cat + -s = ROOT ("cat") + PLURAL
In addition, there are some cases in English where a null morpheme indicates plurality in nouns that take on irregular plurals.
- sheep = sheep + -∅ = ROOT ("sheep") + SINGULAR
- sheep = sheep + -∅ = ROOT ("sheep") + PLURAL
Also, a null morpheme marks the present tense of English verbs in all forms but the third person singular:
- (I) run = run + -∅ = ROOT ("run") + PRESENT: Non-3rd-SINGULAR
- (He) runs = run + -s = ROOT ("run") + PRESENT: 3rd-SINGULAR
A basic radical element plus a null morpheme is not the same as an uninflected word, though usage may make those equal in practice.
See also
- Covert (linguistics)
- Ellipsis (linguistics)
- Lemma (morphology)
- Marker (linguistics)
- Null allomorph
- Zero (linguistics)
- Disfix
References
Note: All of the examples under the Inflection heading come from the same source.