When money talks, no one checks the grammar. – Author unknown

Linguists are no different from any other people who spend more than nineteen hours a day pondering the complexities of grammar and its relationship to practically everything else in order to prove that language is so inordinately complicated that it is impossible in principle for people to talk. – Ronald W. Langacker (b.1942), Language and Its Structure, 1973

The great logical, or grammatical, framework of language, (for grammar is the logic of speech, even as logic is the grammar of reason,) he would possess, he knew not how… – Richard Chenevix Trench, “On the Study of Words,” lecture to the pupils of the D

A double negative is a no-no. – Author unknown