Can someone tell me if this is correct? 私の日本語はいいじゃありません。 私の日本語はいいです。 - Feed Post by Tommhx
Comments 4
The first one is wrong, I think.
Since いい (良い) is an adjective (at least if you mean the adjective "good"), but not a na-adjective but an i-adjective the negative form よくない (良くない)
私の日本語は良くないです
(My Japanese isnt good)
The second is right- Oh gosh, I have omitted some words in my sentences
...the negative form "is" よくない...
...The second "one" is right
僕の英語は良くない XD 
It's pretty what Bakura said. Still, if you want to sound a little bit more natural, instead of いい you could say this:
私は日本語が下手です。
私は日本語が上手です。- pretty much*
