ができたらいいのに

I wish I could

→ が
phrase Rare #30,538
I wish I could Expresses a wistful wish about being able to do something. The word before が indicates what the speaker wishes they could do.
JA: 私ももっと料理ができたらいいのに。
EN: I wish I could cook better too.

僕も日本語ができたらいいのに。

I wish I could speak Japanese too.

僕も英語ができたらいいのに。

I wish I could speak English too.

私も英語ができたらいいのに。

I wish I could speak English too.

話ができたらいいのに

I wish we could talk.

— ベルリン・天使の詩 (1987)