How do you tell Bi and Bidh apart when listening? Is is only contextual?
Pretty sure yes. It doesn't help that some words have... variant spellings.
What a big long word for "soon." Can anyone tell us what it derives from, more literally?
Yes it's pretty much context, as they sound so much alike. Check out Learn Gaelic if you're having trouble with all the forms.
Is it possible there is a better pronunciation of a dh'aithghearr?