In linguistics, inversion is any of several grammatical constructions where two expressions switch their canonical order of appearance, that is, they invert. There are several types of subject-verb inversion in English: locative inversion, directive inversion, copular inversion, and quotative inversion. The most frequent type of inversion in English is subject–auxiliary inversion in which an auxiliary verb changes places with its subject; it often occurs in questions, such as Are you coming?, with the subject you is switched with the auxiliary are. In many other languages, especially those with a freer word order than English, inversion can take place with a variety of verbs (not just auxiliaries) and with other syntactic categories as well.
When a layered constituency-based analysis of sentence structure is used, inversion often results in the discontinuity of a constituent, but that would not be the case with a flatter dependency-based analysis. In that regard, inversion has consequences similar to those of shifting.
In broad terms, one can distinguish between two major types of inversion in English that involve verbs: subject–auxiliary inversion and subject–verb inversion. The difference between these two types resides with the nature of the verb involved: whether it is an auxiliary verb or a full verb.
- a. Fred will stay.
- b. Will Fred stay? – Subject–auxiliary inversion with yes/no question
- a. Larry has done it.
- b. What has Larry done? – Subject–auxiliary inversion with constituent question
- a. Fred has helped at no point.
- b. At no point has Fred helped. – Subject–auxiliary inversion with fronted expression containing negation (negative inversion)
- a. If we were to surrender, …
- b. Were we to surrender, … – Subject–auxiliary inversion in condition clause – see English subjunctive § Inversion in condition clauses
The default order in English is subject–verb (SV), but a number of meaning-related differences (such as those illustrated above) motivate the subject and auxiliary verb to invert so that the finite verb precedes the subject; one ends up with auxiliary–subject (Aux-S) order. That type of inversion fails if the finite verb is not an auxiliary:
- a. Fred stayed.
- b. *Stayed Fred? – Inversion impossible here because the verb is NOT an auxiliary verb
(The star * is the symbol used in linguistics to indicate that the example is grammatically unacceptable.)
In languages like Italian, Spanish, Finnish, etc. subject-verb inversion is commonly seen with a wide range of verbs and does not require an element at the beginning of the sentence. See the following Italian example:
è arrivato Giovanni.
is arrived Giovanni
In English, on the other hand, subject-verb inversion generally takes the form of a Locative inversion. A familiar example of subject-verb inversion from English is the presentationalthere construction.
There’s a shark.
English (especially written English) also has an inversion construction involving a locative expression other than there (“in a little white house” in the following example):
In a little white house lived two rabbits.
Contrary to the subject-auxiliary inversion, the verb in cases of subject–verb inversion in English is not required to be an auxiliary verb; it is, rather, a full verb or a form of the copula be. If the sentence has an auxiliary verb, the subject is placed after the auxiliary and the main verb. For example:
- a. A unicorn will come into the room.
- b. Into the room will come a unicorn.
Since this type of inversion generally places the focus on the subject, the subject is likely to be a full noun or noun phrase rather than a pronoun. Third-person personal pronouns are especially unlikely to be found as the subject in this construction:
- a. Down the stairs came the dog. – Noun subject
- b. ? Down the stairs came it. – Third-person personal pronoun as subject; unlikely unless it has special significance and is stressed
- c. Down the stairs came I. – First-person personal pronoun as subject; more likely, though still I would require stress