1) Most normal people who love language enjoy words such as sublime and kerfluffle, and the subtleties of meaning in the word "grace". Linguists write articles about "the" and "or".
2) Normal people laugh at the funny things kids say. Linguists draw 12 level tree diagrams of the same 5 word sentence. Oh, it's a subjacency rule violation in an object reduced relative clause under a high memory load. That clears things right up, doesn't it?
3) A linguist's idea of a relaxing time with friends is to make up fake dialect maps of the various names of scotch tape. (It was on the dept. lounge board for a month.)
4) Normal experts in the English language wax rhapsodically about the Pathetique in George Eliot. Linguists don't have much to say about anything that's longer than two sentences. To be honest, one sentence is really fine; thank you very much.
5) Normal language teachers correct student essays in order to make them sound more persuasive. Linguists lecture their class on all the reasons "ain't" is a great word. (Me on Wednesday with my students.)
6) A linguist says the word monophthong without giggling.
7) A normal lover of language studies French and German and Thai and tries them out every chance she gets! A linguist will argue for governmental policy that supports bilingualism and trilingualism, but only speaks English decently.
8) A normal person looks up a word in a dictionary and believes what it says. A linguist looks at the entry and goes, "pff, how much was Jack drinking that day?"
9) A linguist loves to say things like, "When a noun N is followed by an adjective A in sentence S...." because it seems so much more mathematical with capital letters like that and people respect mathematicians! Usually, the abbreviations A are never used U again A1.
10) When a normal person learns a new language, they quickly learn how to ask, "where's the bathroom?" A linguist quizzes the person about the language's pronoun system. "Hey, it an inclusive vs exclusive 1st p sing system again!"