Hi,
Could someone explain when to use ‘on’d yw hi/e’ and when to use ‘on’d ife’.
e.g.
mae’n mynd yn glou iawn ar y penwythnos, on’d yw hi? (It goes very quickly at the weekend, doesn’t it?)
mae’r amser yn hedfan heibio, on’d ife? (The time flies past, doesn’t it?)
Many thanks,
Andrew
I’ve always thought it was whatever slips best off the tongue, but there may well be a rule. I always wondered myself if I’m supposed to switch from fe to hi, depending on what’s gone before, because yndife just seems to pop out of my mouth without thinking these days - even for the weather and would like to know if I’m supposed to switch to yndw hi etc. Thinking about it ife is probably nothing to do with fe or hi, so probably safe?
Doesn’t it depend if the it refers to a masculine or feminine noun? Or hi if it’s generic? Just a guess, though!
In theory, but ife tends to get used for anything.
Well my guess was based mostly, if not only, on SSiW examples where all three are present. My ears are not skilled enough to notice and remember what I’ve heard on TV or speaking with people!
And you’re not wrong at all! This ia a case where natural usage often doesn’t always match theory. If you followed you’re answer you’d be 100% right but you’ll also hear “ife” for masculine, feminine and generic too 
Well I’m glad to hear that I seem to have understood the theory. 
However since at the moment I remember just a handful of Welsh noun genders (is this the correct name for it? I don’t know!), I have to confess I always say a totally random one when I do challenges.
And of course even more so when I try to speak! 
So I get that fe/hi are masculine and feminine but still not sure where ‘ife’ fits in…
This is my take on it:
“Ife” is “yw fe” shortened - “is it?”
“On’d yw fe” can become “d’fe” or “ife”, “isn’t it?”
It’s a tag at the end of a statement to make a question, helps a converstation flow. Can also just be used as a response:
“Mae’r bws yn hwyr” - the bus is late
“Ife?!”
Although I tend to err towards Gog so use “ynde” or “tydi” etc.
Aha. The penny has finally dropped…thanks Anthony. Now I get it and will sleep better tonight!
Andrew