If I were able to speak English, I think that would take care of half my worries.
If I could learn to speak English, I think half my worries would be solved.
ーIf I were able to speak English, I think that would take care of half my worries.
「英語が話せたら、私の悩みの半分はなくなるだろうに」
to take care of half my worries で「私の悩みの半分を対処する・処理する」
ーIf I could learn to speak English, I think half my worries would be solved.
「英語が話せたら、私の半分の悩みは解決するだろうに」
half my worries would be solved で「私の悩みの半分を解決するだろう」
ご参考まで！
Half of my worries would disappear if I could speak English.
こんにちは。
様々な言い方ができると思いますが、例えば以下のような英語表現はいかがでしょうか：
Half of my worries would disappear if I could speak English.
英語が話せたら悩みの半分はなくなる。
disappear は「消える」という意味です。
ぜひ参考にしてください。
カナダ 
アメリカ合衆国 
