This is a totally speculative answer, as it is about predicting the future, but I will take a stab at it.
Further Interaction of Information
Depending on the demographic, the phone will be more than "one-way." I don't mean to suggest that it's not interactive already, but that more data from our phones will be collectable. My blood sugar level from a sensor, her rapid HIV scan, his appraisal of the room ("is the light in this cafe optimal for reading?"), and our wine's preliminary taste-by-phone ("how high is the sulfide level; how many tannins are there; how many calories does this have?"). And so on.
Watching when mobile phones incorporated cameras was fascinating. Soon, they should be able to do more things, like a Swiss Army knife. Some phones (or watches, or devices) may be able to read a book out-loud to a child, repel mosquitoes (ha), even clean the air around you; these are things that require larger devices today, but remember how big a camera was in 1980?
Perhaps a phone can not only detect water quality, but purify or sterilize it: again, of course this requires a lot of work today, but maybe in the future, it requires a tiny device: don't underestimate materials-science. Similarly, it may provide educational interactive information and way-finding for civic resources.
I'd really love phones/watches/devices to incorporate an easy button or gesture that alerts emergency services to you ASAP. Of course, since I butt-dial people all the time, I would hope it's a procedure that is easy, but not accidentally activated.
This is all purely speculative, of course.