Yes, unless "erbyn" is in the context of "Lloegr yn erbyn Cymru", for example.
Yep, I'd learn erbyn and yn erbyn separately:
erbyn = "by" (time)
yn erbyn = against
Quite a useful word, with several meanings:
- Byddwn ni yno erbyn wyth o'r gloch - We'll be there by eight o'clock
- Erbyn i ni gyrraedd, roedd hi'n dywyll - By the time we arrived, it was dark
- Erbyn hynny, roedd hi wedi gwella - By then, she had got better.
- Erbyn meddwl... - Come to think about it...
- Mae Cymru wedi ennill yn erbyn Lloegr - Wales have won against England (yn erbyn - against)
Would "Erbyn i ni" need to be used in the example "Erbyn i ni gyrraedd", or could it be said/ written as "Erbyn gyrraeddon ni"?
It's the first suggestion, 'erbyn i' + pronoun = by the time I/You/He etc arrived
Diolch. So Erbyn i fi, Erbyn i ti, Erbyn iddo fe/fo, Erbyn iddi hi, Erbyn i ni, Erbyn i chi, Erbyn iddyn nhw.
Yes, followed by the mutated verb.
eg Erbyn i fi ddod = By the time I came/come Erbyn iddyn nhw adael = By the time they left/leave
The tense of the phrase depends on the rest of the sentence.
eg. Erbyn i fi ddod roedd hi'n bwrw glaw = By the time I came it was raining
Erbyn i fi ddod bydd hi'n bwrw glaw = By the time I come I will be raining