text a message? Seriously We usually have no problem communicating while riding, when she wants to convey something she will lean into my left ear, and when I want to convey something I simply scream HANG ON WE'RE GONNA DIE!!!!!
I've started trying to use some of the SCUBA hand signals to communicate similar things on the bike. The only real difference is down means 'slow' and up means 'speed up' as opposed to descend and ascend (sorta opposite meaning while riding than SCUBA)