They stared back at her as if she'd spoken to them in an alien language.

At that time, his choice of an alien language was unique.

She had made several efforts to learn what was known of the alien language.

They were talking some mix of their own alien language and ours.

The book contains what was probably the first alien language in any work of fiction.

I'm not sure I can take another alien language right now.

He spoke like a man who uses an alien language.

"Who knows what an alien language looks or sounds like?"

Harry felt certain she had suddenly begun to speak an alien language.

For her he might have been speaking in an alien language.