It would be interesting to study folk beliefs about language, using people's complaints about phrases they don't like or think incorrect as the evidence.

1. Language is fundamentally logical, and phrases that can't be taken literally should not be used.

For example, on one of the sites in which people were complaining about phrases, several complained about the phrase "There you go," (a server says this when setting food down for you at a restaurant) on the grounds that no, "I am not going anywhere."

2. Labels are descriptions

A preposition must come before something because the prefix "pre" means before.

3. The true meaning of a word is its etymology.

4. What my English teacher taught me must be right.

5. The true meaning of a word is what it meant in my parents' (grandparents') generation.

6. Linguistic change is (almost always) for the worse.

7. My dialect is better than other people's.

8. A word should only be one part of speech.

If something is more noun than verb, you shouldn't use it as a verb.

9. It is possible to protect or improve a language "academically."

The motto of the Royal Spanish Academy of the Language is "Limpia, pule, da esplendor."

10. Younger people speak worse than older ones.

(see also number 6 and number 5)

11. A word's correct pronunciation should reflect its morphology

Someone objected to the pronunciation "kil-Ometre" alleging that "there is no such thing as an 'Ometer.'" He preferred to pronunciation "KIlo-MEtre," which is his right. But there is no inherent reason why the word should break up phonetically into its morphemic structure.

12. Americans speak worse than Britons.

13. If at any time someone has proposed to distinguish between two words, like "continuous" and "continual" or "uninterested" and "distinterested," that distinction should hold for all time.

You still find people saying you can only "rear" children, never "raise" them.

14. The writing system of a language is an essential part of its structure.

15. Variant pronunciations of words are signs of ignorance; the letters of a word should always be pronounced in the order in which they appear in the word.

I'm sure there are more such "folk beliefs." These are just the ones that occur to me.