I remember seeing parts of an old sci fi movie about a group of people on an alien planet. The aliens kind of look like bugs. One of the people in the group is a woman who is trapped by the aliens, and I think they're (the aliens) learning her language.
There is a scene like that in 'The First Men In The Moon'.
The story takes place on the moon, the aliens look like stop-motion insects, a woman is captured and held in a transparent cage while the insects try to communicate with her via a flashing crystal.
The insectile aliens can be seen around the minute mark in this trailer: