informalthat

Informal that refers to the optional omission of the complementizer that before a subordinate clause in English. It is a common feature of spoken language and informal writing, where speakers frequently drop that after verbs of thinking, believing, saying, perceiving, and other reporting verbs.

Choice of verbs and clauses: The omission is widely observed after verbs such as think, suppose, believe, guess, know, say, tell, report, hope, assume, and feel. For example: I think (that) you’re right. She said (that) she would come. We know (that) he lied. In informal speech, the sentences without that are generally understood as expressing the same meaning as the ones with that.

Usage and style considerations: Dropping that is generally avoided in formal writing or when its absence could cause ambiguity or misinterpretation, particularly with long or complex clauses. In many dialects, including most forms of American English, that-deletion is widely acceptable in casual conversation, while some varieties of British English emphasize retaining that in more careful speech or writing. The presence or absence of that usually does not change verb tense or aspect, but it can affect perceived formality and fluency.

Historical and variation notes: The use of that has declined in informal speech over time, yielding a more conversational style in many English varieties. Nonetheless, that remains a grammatical option in appropriate contexts, with its acceptability varying by dialect, register, and the length or complexity of the subordinate clause.