> Linguists have resorted to spying on people in parks and shops and restaurants, to get "natural" language unperturbed by observer effects, audience tailoring, the filter of writing, etc.
Hence the common phrase, found in most language phrasebooks: “is that a linguist hiding behind that bush?”
That’s what makes ethnolinguistics fascinating. As a native French speaker, I started getting interested by linguistics when I learned Italian, and now I keep noting things I never thought about when I talk with other native French speakers. As someone said, “You don’t know your language until you know another one”.