What does Proverbs 10:32 mean?

There are two ways to interpret the term "know" in this context. One is the idea of information and awareness, the other is of experience. Both apply to the words that naturally come from those who are spiritually wise, and those who are foolish. Wise people know the correct things to say (Proverbs 10:13), and when it's best not to speak, at all (Proverbs 10:19). Wicked people are inclined to saying hateful or inflammatory things (Proverbs 10:18), knowing full well they're being unreasonable (Proverbs 10:23).

When Jesus spoke in the synagogue at Nazareth, His words greatly impressed the listeners. They "spoke well of him and marveled at the gracious words that were coming from his mouth" (Luke 4:22). The Bible has given us sufficient teaching about gracious speaking that we know what words please Him and bless others. Sinful speech does not stem from a lack of knowledge but from a disobedient heart. The wicked also know what gracious speech is, but they choose to employ perverted speech. Because their hearts are corrupt, their mouths utter corrupt language.

The problem of this kind of sin is not about syllables or sounds. What constitutes inappropriate speech varies drastically by culture and region. The intent is what matters—and this is a major problem with modern culture. Today, language in movies, music, and television is often offensive for the sake of being offensive. The same often applies to speech heard in public. Wisdom produces acceptable speech, whereas a lack of wisdom produces offensive, perverted speech. That so many people in the modern world rely on warped words is an indictment of the culture's spiritual health.