The movie Tombstone, was one of the greatest western movies of all time. One of the most intriguing scenes is where Val Kilmer as Doc Holiday, and Michael Biehn as Johnny Ringo converse in Latin. The scene carries an air of mystery because their conversation is unknown to us, however the conversation is even more interesting when interpreted because it is full of hidden meanings and aphorisms that say many things at once.

The scene is in the casino that Wyatt Earp is running, immediately after a play in the nearby theatre. Jonny Ringo comes in with his gang and confronts Doc Holiday. Right before the conversation Doc Holiday says "He reminds me of me, now I really hate him". Tempers flare in the Latin conversation and result in Ringo showing off his gun wielding skills by twirling his revolver around. Doc then lightens the mood by imitating him with his small liquor cup. If you ever wonder what they said in that short Latin scene, here is the full dialogue as well as the translation.

Doc : In vino veritas.
Ringo : Age quod agis.
Doc : Credat Judaeus Apella, non ego.
Ringo : Juventus stultorum magister.
Doc : In pace requiescat!
That was the Latin, and here is the translation. Note that the phrases are fairly common and a direct translation would not make much sense. Look at their individual write-ups for a more thorough explanation. I have added a brief paragraph explaining the lines one by one as I interpreted them.

Doc : In wine there is truth.
Doc Holiday is excusing his own behavior here, and further insulting Johnny Ringo by saying that he is drunk, and saying truthful things he would otherwise not reveal. He had previously said he hated Johnny Ringo for being similar to himself.
Ringo : Do what you do / Watch what you do.
This is one of the most interesting lines because it means more than just watch what you do. The line can be interpreted as be careful, or people do what they do (saying that Doc Holiday is drunk because he is a drunkard), and it can also mean something along the lines of do what you do best, which would be gunfight since Ringo had apparently heard of Holiday's skill. It is a challenge and an insult combined into one.
Doc : Tell it to someone else, not I.
This line is dismissive. Doc Holiday is conveying the fact that he doesn't care what Johnny Ringo is saying and that he doesn't care what his advice is.
Ringo : Youth is the teacher of fools.
When Ringo taps his pistol he says this, which conveys the idea that Doc Holiday is inexperienced (youthfull) and ignorant of the danger he is getting himself into.
Doc : Rest in peace!
To end the conversation Doc Holiday throws the previous warning back into Ringo's face. Doc tells him to rest in peace, or to die, because Ringo is unaware of the danger that Doc presents.
The conversation, at first, does not seem to flow well, but there are several hidden meanings and ideas being passed back and forth. The use of these Latin phrases carries a lot of symbolism and meaning in the way they were used here. Now you know what the phrases translate, so go watch it again, this time with the knowledge of what they say so you can find the hidden implications of their conversation.