Yeah I was just pointing out that saying はい in that situation may seem a little arrogant from what I've heard.

Also just as a quick comment on the sentences you post.

A: 日本語がじょうずです。
B:　いいえ、じょうずではありません。

Would be more accurate as the wa sound in ではありません is written as は not わ. Just thought I'd say in case you were unsure. But I didn't even understand the last sentence you posted so you're probably better than me at this.

Also a quick question since you seem more knowledgeable on this than me. In your first sentence why is it 日本語がじょうずです and not 日本語はじょうずです? I know that が is correct in these kind of adjective sentences (at least I think that it's that way using the common sentence (something)が好きです。as an example) but I don't know why. Well since I'm an sort of unsure about a lot of Japanese as a whole (being a beginner and since you said you were unsure) we can't even completely confirm that the sentence is valid. But I would be interested in finding out about this (although I should probably stop while before it's too late, I could be digging myself into an even deeper hole here).

Ok I will attempt to help, but I will say that I do not consider myself an expert, and if someone like Ronin, MMM, ect come in and make corections, they are the ones to listen too.

The second part of my second sentence could be wrong, I am unsure how to spell it since I have only heard the phrase verbally. So for now just ignore it. When I learned じょうず (skilled at),　I learned いたい (pain)　and 好き (like) along side it. We used が　for all of them. The way I understand it is you dont use は　becuase it is not the subject. If you would extend the sentence it would be : あなたは日本語がじょうずです。

So the subject would be あなた　(you). Again this is my understanding.

Would it not be あなたの日本語がじょうずです?

Also I think you mean topic. が is the subject marker.

ah yes is should be topic marker, my mistake.

uwaaa =.=
you guys are much more knowledgeable about grammar than i am >.<'''

if it were me though
i typically leave out the 'anata" part and just say


"uwaa.... nihongo jyoozu desu"
but i guess if i were to include anata
i'd say "anata no nihongo wa jyoozu desu" as well >.>''

Yes the あなた would normally be left out. Also don't forget that particle inbetween 日本語 and じょうず.

I often hear that particle omitted too, though, in casual conversation. And then there's that ubiquitous "ね"　you might tack on to the end. :D

Wave your hand in front of your face and say いいえ. Relatedly, when you give a gift to someone, you could precede it with something like たいしたものじゃないけど...

I learned that you can say いいえ、へたですtoo.I think it's the same,though,because as far as I know へた is anothe way of saying じょうずでわありません,but it's shorter:D

I may be wrong but I vaguely remember reading somewhere that が is very rarely emitted.