YOU SAID:

if you can't fly; walk.

INTO JAPANESE

飛べないのなら歩く。

BACK INTO ENGLISH

Walk if you can't fly.

INTO JAPANESE

飛べない場合は歩いてください。

BACK INTO ENGLISH

If you can not fly, please walk.

INTO JAPANESE

飛べない場合は、歩いてください。

BACK INTO ENGLISH

If you can not fly, please walk.