No - in Welsh. I'm afraid it depends on the nature of the question.
Whether it is definite or indefinite. e.g.:
Is there a book here? = Oes llyfr yma?
Answer/Ateb = Oes mae llyfr yma - Yes there is a book here.
or / neu : Nag oes, does dim llyfr yma. No there isn't a book here.
and again ... May I go to the toilet. = Ga i find i'r ty bach?
Yes = Cer or cewch, depending on how well you know the person!!
No = Na cher or na chewch.
Again ... Do you want a car? Da chi'n moyn car? Yes = Ydw, diolch.
or No = Nag ydw, dim diolch.
There was a typo in my last answer - sorry but AB's spell check is a bit too vigorous as far as Welsh is concerned!! In the text there is 'find' that should of course be "fynd". Also; as far as pronunciation is concerned these 2 links may help:
http://www.cs.cf.ac.uk/fun/welsh/lesson01.html
Thanks / Diolch - Oh I do agree, also on my last link the 1st one has been amended to:
www.cs.cf.ac.uk/fun/welsh
then from the options choose Lesson that relates to pronunciation.
No, not at all. Welsh is a fully recognised OFFICIAL language of the UK, and with say 800,000 speakers in the UK, and a further say 200,000 as a Diaspora. btw I'm not demanding, it was/is submitted as a suggestion - but a very valid one.
Please see my previous answer, and to Boo, don't worry I won't stoop to insulting the English [or any other Linguistic Group], if that's what you are!!
Seems as if I've lost on this one!. I'll post any extras under "Society & Culture".
Hope that's ok. Thanks to all who responded, favourably or not ! Diolch yn fawr iawn i chi gyd.