Https://ubrp.arizona.edu/study-finds-no-difference-in-the-amount-men-and-women-talk/

Average man uses 15,669 words/day, woman uses 16,215. Let's say average household has two people and half those words are spoken at home, 31,884/2 = 15,942. Let's say 8 bytes per word on average, just under 128k/day. That's a little under 47 MB/year. Not too expensive.

Edited with better source/numbers.