These speakers appear to be a part of the wall itself.

There doesn't have to be a sender or receiver in these cases, even though a prominent speaker of the new thought usually appears.

The speaker appears to be generalising to a time which includes her own experience.

Peering through the coarse grass he saw the speakers appear.

The last speaker appeared to be a sort of sub-lieutenant.

The invisible speaker appeared to give this some consideration.

A speaker appeared in the wall of the crawl space.

The speaker now appeared from higher up the slope.

Hand to her breast, she turned as the speaker appeared.

The two speakers appear to have read a different Commission document from the one I am familiar with.