The deep river was an insuperable barrier to those who could not swim.

对不会游泳的人来说，这条深河是无法超越的障碍。

youdao

The development of English into the world's lingua franca suggests that spelling is not an insuperable barrier.

ECONOMIST: The conflict in Georgia

The presence of the toxic Mr Lieberman in the foreign ministry is not itself an insuperable barrier to negotiation.

ECONOMIST: Israel's new government

In years past Turkey's spotty democracy was often cited to prove a negative: the Turkish case (along with Indonesia's and Malaysia's, also with reservations) showed that Islam did not pose an insuperable barrier to multiparty democracy.

ECONOMIST: The Turkish model