In English we might also say 'It is 5 past 4'. Is this sometimes said in Welsh or do you ALWAYS have to add 'minutes'
Keeping the munud in there is usual.
Is there a grammatical reason that the "p" dropped off "pump"? I know the initial change is due to soft mutation but I'm not sure about this change.
In the standard language pump, chwech and cant all drop the final letter before a noun, adjective etc ->; pum, chwe, can
This does not always happen in informal usage.
Diolch yn fawr iawn!