I am wondering since english people speaks english, which is their language, how come people from scotland, wales, Ireland, Northern Ireland speaks english too?
is it because england swallowed up their countries in ancient past, that they too speaks english till now?
Yes
no wonder they hated the english very much.
they also have their own languages, like scottish, welsh and gaelic isnt it?
Yes. All part of the greater Celtic family of languages. Which are the original languages of the whole of the British Isles.
damn the english. I think the scots, welsh, Irealish people hated the english to the core.
The current generation do not hate. Because they did not care much about history. It was those generations in the past whom were punished in class for speaking Welsh, are those who hated. The most famous example is the "Welsh knot" punishment.