Linguistics is hard. Bob Laughlin, creator of the amazing Tzotzil dictionary, did some fun experiments about the use of native-speaker informants, by testing A

Linguistics is hard. Bob Laughlin, creator of the amazing Tzotzil dictionary, did some fun experiments about the use of native-speaker informants, by testing American undergraduates’ knowledge of breakfast cereals. There were some respondents who mixed up the cereals. Some who put them in a few categories (something like "cheerios", "flakes", and "cereal"). Some who left most of the questions blank. One respondent identified all of the cereals as “shit”, “shit”, “shit”, ... The best informant correctly identified 5/8 cereals. One of the presented cereals was actually toucan food, which was identified by various informants as “raisin bran”, “grape nuts”, “grapenuts flakes”, “fertilizer scented breakfast food”. https://repository.si.edu/handle/10088/1360 https://repository.si.edu/handle/10088/1360 (see the introduction, pp. 9–12)