It is Oes and ydy and ia/ie and do... there are quite a few depending on the context!
You don't quite say "yes" or "no" in Welsh. If someone asks you a question like, say, "are you going to the gym after lunch?" instead of saying yes, you'd say "I am." And if you weren't you'd say "I'm not." It means there's a lot of variants for the yes/no equivalent answers to many questions with different verbs (are you, will you, did you, did she, are they, would they, etc etc). But on the upside, it avoids ambiguity in questions like, "you didn't cheat on the test, did you?" where in English, 'yes' could either mean yes you did cheat, or yes you didn't cheat.
Oes - a general 'yes'. Use this if you're not sure how to answer a question you're asked in the particular case.
ydw - I am
ydy - it is
ia/ie - sort of like 'yeah'
etc, etc, etc.
The Welsh word for Excellent is ardderchog, it is also the welsh for fantastic.
The Welsh word for mum is mam.The Welsh word for dad is dad.
The Welsh word for 'a cave' is ogof.
The Welsh word for Epiphany is Ystwyll.
'You' is not a Welsh word.
Yes, the noun 'Welsh' is a word for the people of Wales. The word 'Welsh' is also an adjective, a word to describe something as of or from Wales.
The Welsh word for Toxic is: Gwenwynig
The word 'fern' is not a Welsh word and has no meaning. The Welsh word for 'a fern' is 'rhedynen'.
The Welsh word for 'decibel' is desibel.
The Welsh word for Excellent is ardderchog, it is also the welsh for fantastic.
The Welsh word for mum is mam.The Welsh word for dad is dad.
The Welsh word for planet is 'planed' (plural - planedau)
the welsh word for trust is 'ymddiried'
The Welsh word for 'landowner' is 'tirfeddiannwr'.
The Welsh word for 'a cave' is ogof.
The Welsh word for Epiphany is Ystwyll.
The Welsh word for 'rectangle' is petryal.