Live among men as if God beheld you; speak with God as if men were listening. Seneca
No matter how just your words may be, when you speak with anger, you ruin all: no matter how boldly you speak, how fairly reprove, or what not. John Chrysostom
In Paris, one is always reminded of being a foreigner. If you park your car wrong, it is not the fact that it's on the sidewalk that matters, but the fact that you speak with an accent. Roman Polański
You may speak with your gold and make other tongues silent. Danish Proverb
Write with the learned, but speak with the vulgar. English Proverb
Speak with a true heart, holding back your evil passions. South American Proverb