insurmountable

语言障碍似乎是一个无法克服的难题。

The language barrier appears to be an ___insurmountable challenge.

这座山太高了，对我们来说是不可逾越的障碍。

The mountain is too high and presents an ___insurmountable obstacle for us.

语言障碍对于初学者来说似乎是一个无法克服的困难。

The language barrier seems like an ___insurmountable difficulty for beginners.