I had the good fortune to speak to Joe Griffin about this recently.
He indicated that people often
think they are talking and hearing language in dreams when what they are hearing and saying are, in fact, impressions of language.
The evidence for this comes from people who have written down supposed conversations after waking from a dream period and then reviewed what they had written the next morning--only to discover that what they had written was gibberish.
I put it to him that if, however, language and images of people do in fact appear in dreams as they would in reality (i.e. correctly synchronised) then an interesting problem arises : what is doing the synchronising of image and language? The difficulty is this: a) the left cortex cannot make sense of where, in an image the appropriate language section should go because it does not know how to decode images and b.) the right cortex cannot make sense of the language sequence from the left cortex in order to match it up to the correct images. It would appear that a separate brain process is able to synchronise these.
When I put this conundrum to Joe Griffin recently he simply said "But we do it in waking life all the time! There are processes which are capable of doing this.". He is, of course, right.
How do we do it given that language and images are processed by different areas?
This question can now be asked about image / language synchronisation in the waking state.

An apology: all of this is, naturally, rather academic and may not be of practical interest to many of the people who visit these forums. They are interested in offering and getting help for real problems and I do realise that this is the main function of the forums.