>>22203
Yeah, that is a part of it too but if you count teineigo then there are like 20+ ways of saying it. I am not counting every permutation, I mean that you can say
帰らなければいけない
帰らなくちゃいけない
帰らないといけない
帰らなくてはいけない

2 is the shortened version of 4 but that version then has a further shortened version, 3 has a shortened version, too and all of them could be written with like 3 or 4 different main predicates (the ikenai could instead be dame, naranai, sometimes omitted etc)

Pure bred bri'ish folk just say "Gotta do it, innit mate" and thats ENUFF