Entirely out of place is obscene, silly, and vulgar talk; but instead, let there be thanksgiving (Ephesians 5:4).
When my oldest daughter was four years old, she asked me for some Ramon noodles because she hadn't "had any of those d*%$n things in a long time." It was a funny way of asking for a something and the origin of the word was clear (straight from her daddy's mouth...okay maybe mine too :).
Obscenities are something my little family could work on, but also trash talk and destructive speech. I remember when I was a child and someone was mean to me I naturally would want to put that person down as well. My mom would always prod me to find out what kind of life did this person have. What was the cause of her not-so-nice behavior toward me? My mom's questions forced me to not only take a look at how my behavior may have contributed to the problem, but it also set up patterns of empathetic thinking toward others that I carry with me today (at least I try). Thinking this way stopped a lot of the destructive speech that I may have delved into otherwise.
One other way to check what is being said in the home is to question if I would say it if Jesus were standing there listening to me or if I were in a church.