I've been really wondering if "what" of the relative pronoun can be treated as plural. A dictionary or a certain book says it's generally singular. But it doesn't make sense to me. I suspect that "what" 's plural form has been incorrectly used and tolerated. Otherwise no book would exaggerate it. Perhaps the book tells lies. I'm so confused.

See a translation

I found these examples:

They did what other people do.
(This "what" implies "the things which", not "the thing which")

What Japanese intend as gestures of friendship are sometimes misunderstood and thought to be signs of flattery
(The verb isn't "is" but "are". Besides, not "a sign" but "signs")

They are what make you fat.
(This "what" clearly refers to plural things, and the following verb isn't "makes" but "make".)


I know that these examples are not incorrect. But many books or websites note that "what" is usually used as the singular. I want to know the reason. (I repeated this for fear of misunderstandings.) Could you tell me the reason?

@ajxoul So, you mean such notes are strange and absurd?

I see. It's all clear now! Thank you so much (*´∀｀*)♪