Examples taken from here.
The following restriction applies in many languages:
*Shei said that Maryi gave a great talk.
Yet, embedding the pronounis permitted:
[Heri colleague] said that Maryi gave a great talk.
Embedding on the other side doesn't have a similar effect:
*Shei said that [Maryi's student] gave a great talk.
This is a peculiar restriction. However, we could imagine a language that does the opposite, not permitting [Heri colleague] said that Maryi gave a great talk yet permitting *Shei said that [Maryi's student] gave a great talk.
This would be an even peculiarer restriction, since it would not be terribly easy to explain by recourse to X-bar or the like, which is easier to do with the English situation.