I always leave the subtitles on. For me it's not too distracting, let's me catch words that I might have missed, and gives one more benefit: at a glance I can recognize a character response that I've already gotten. In many games you can click through the rest of the response and move on. Without subtitles you'd have to listen a while longer before being sure the response is a repeat. Guess I'm a little impatient at times.
I point, therefore I click.