Around here, if somebody is talking into a phone on the train, they get dirty looks. It really is not at all common and pretty awkward. I have never witnessed anybody give a voice command to their phone.

At work, we isolate the frequent-phoners from those who have to concentrate for prolonged periods of time. If more poeple start talking at work, the distractions are going to get worse.

Actually, only those who are talking loudly into a sensitive microphone held right next to their mouth get dirty looks. Plenty of people sit there having a quiet conversation and even from the seat in front or behind you can't hear them speaking