In Angus Watson's dictionary 'home' is given as dachaigh. Why does it have to be written 'dhachaigh' to be correct here?
dachaidh is a noun "a home", the adverb is dhachaidh "home(ward)".
Thanks for the distinction. This is spelled dhachaigh? Is there a difference in meaning?
It has directionality. It is used with movement verbs to indicate movement homeward.
Wait, what? Home is an adverb?!