fastfinge 2 points
I don't know if it's genetic, but I do know families sound similar to one another. Accent, of course, is the big one. But families will often speak with a similar inflection (how far in pitch do they go up for questions, how long do they pause between sentences, how emphatic are exclamations and in what way, what volume do they usually speak at), and make similar word choices (folks vs. people, soft drink vs. soda, choice of curses/surprised exclamations etc). I can often make a good guess that two people are related, or at least lived together for a long long time, even if they have totally different vocal sound, based on intonation and word choice.