Zero (linguistics)
In linguistics, a zero or null is a segment that is not pronounced or written. It is a useful concept in analysis, indicating the lack of an element where one might be expected. It is usually written with the symbol "∅", in Unicode. A common ad hoc solution is to use the Scandinavian capital letter Ø instead.
There are several kinds of zero:
- In phonetics and phonology, a null phoneme or zero phone indicates that no phone is produced where one might be expected. For example, in syllable structure analysis, a null onset indicates that a syllable lacks an initial consonant that is normally required by the phonotactics of the considered language. For example, see Standard Chinese phonology#Zero onset.
- In morphology, a zero morph, consisting of no phonetic form, is an allomorph of a morpheme that is otherwise realized in speech. In the phrase two sheep ∅, the plural marker is a zero morph, which is an allomorph of -s as in two cows. In the phrase I like-∅ it, the verb conjugation has a zero affix, as opposed to the third-person singular present -s in he likes it.
- In grammar, a zero pronoun occurs in some languages. In the English sentence nobody knows ∅ that the zero pronoun plays the role of the object of the verb, and in ∅ makes no difference that it plays the role of the subject. Likewise, the zero pronoun in the book ∅ I am reading plays the role of the relative pronoun in the book that I am reading. In generative grammar, this is also referred to as PRO. In pronoun-dropping languages, including null [subject language]s such as most Romance languages, the zero pronoun is a prominent feature.
- A zero subordinate conjunction occurs in English in sentences like I know ∅ he likes me, in which the zero conjunction plays the role of the subordinate conjunction that in I know that he likes me.
- A zero article is an unrealized indefinite or definite article in some languages, such as the plural indefinite article in English.
- A zero copula, in which a copula such as the verb to be is implied but absent. For example, in Russian the copula is usually omitted in the present tense, as in Она красивая. In English the copula is sometimes omitted in some nonstandard dialects.