1. I wish I were good at ja dance.
2. I wish I were good at ja dances.
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Which on is grammatical?
Sorry -- but I don't know what ja dance (or dances) is.
Change "dance" to "dancing" and it'll be fine.
The grammatically correct sentence is: "I wish I were good at ja dance."
Explanation: Both sentences express a wish to be good at ja dance, but the first sentence is grammatically correct. In English, when using the verb "wish" to express a hypothetical or unreal situation, we typically use the subjunctive form of the verb "to be." In this case, the correct subjunctive form is "were," regardless of whether the noun "ja dance" is singular or plural.
To arrive at this answer, you can consider the grammatical rules of English verb forms and how they are used with "wish" to express unreal or hypothetical situations. Additionally, consulting a grammar guide or a trustworthy source can provide more detailed explanations on using the subjunctive form correctly.