In "I Keep Six Honest Serving Men" of Kipling there is a line:
But different folk have different views;
Notice, the word folk here is obviously in plural, but has not -s ending. Kipling had no need to change the grammar in that point - folk instead of folks does not change neither rhythm nor rhyme. That means, he felt this variant as more suitable for plural here. So, it is absolutely English, I only have to understand it.
But in dictionaries I see:
folk or folks [PLURAL] INFORMAL people in general (Macmillan)
Free Oxford gives more interesting variant:
folk (also folks) informal [treated as plural] People in general.
So, according to the last, ‘folk’ can be considered as plural of ‘person’. But in the same dictionary, or in several others that I checked, (including paper big Macmillan or Concise Oxford), in the article for ‘person’ you will never see ‘folk’ as a plural form for it.
The question Should it be folk or folks? has nothing in common with my question. The mentioned problem is about the plural form of the word
folk. It is NOT the case of the mentioned Kipling's line. And it is already written in the question. (Obviously, somebody reacts to the titles not reading the content.) I am talking about the
folk as plural for the
person -the problem never touched in that other question.