Do you dictate differently than you normally talk? Or do you tell people who have conversations to be worried about their voice chords?
Example of a non-strenuous dictation task: if I am driving, my Android will read my texts and allow me to reply by voice, a speech-to-text and text-to-speech task that is damned handy.
Conversation between multiple people doesn’t involve one person speaking continuously for hours. As such you can spend a lot more hours per day dictating than is normal, that’s the risk not simply talking an extra 20 minutes per day.