Os and Pe

When would you use ‘os’ as opposed to ‘pe’ for ‘if’.
Thanks in anticipation of a reply.

pe is used for hypothetical or non-real situations and is mainly used with the conditional tense.
os is a more open ‘may or may not’ and is used with present and future tense.


Exactly as Siaron has summarised it.

Os ydy e gartre - If he is at home (may be true at the present moment, or may not)
Os bydd y bws yn hwyr - If the bus is late (may happen in the future, or may not)
Pe bawn i’n gyfoethog - If I were rich (but I am not)

And remember that taswn etc = pe bawn etc


Thanks Gareth.Is pe bawn a Northern way of saying this and tawsn the southern equivallent? I’ve not seen pe or pe bawn to nmy recollection and I’ve mainly been exposed to DeCymraeg

pe bawn is a more formal version, so you’re more likely to see it written than hear it in everyday conversation.
I love this song by Al Lewis Band though that uses pe cawn - ‘If I could’ or ‘If I were able to’