Lock 2 AIs that haven't been programmed with language in a room, given time do they develop the ability to communicate and express ideas, desires, needs to each other?

There have been several instances of language evolving again, deaf people creating sign language, etc. A sentient intelligence should be driven to understand concepts and convey them, probably over multiple mediums.

That's why the turning test is a good start, communication is a key aspect of sentience but its just round one.