Because I think it would be just pretty cool if I were able to speak English.
Because I just think being able to speak English would be pretty awesome.
Because I just think being able to actually speak English would be a pretty cool feat.
ご質問どうもありがとうございます。
様々な表現があると思いますが、いくつか自然な表現を紹介します。
- Because I think it would be just pretty cool if I were able to speak English.
- Because I just think being able to speak English would be pretty awesome.
- Because I just think being able to actually speak English would be a pretty cool feat.
--- feat= 手柄、功績、妙技、業績
P.S.
一方、「英語が話せる人ってカッコいい」を英語で表現する場合は、
下記の言い方ではいかがでしょうか。
・I just think people who can speak English are pretty cool!
お好みに合わせて使い分けてみてください。
ご参考にしていただければ幸いです。
ドイツ 
モロッコ 
