Living languages are strange creatures. What makes a language living is not merely that the language is still spoken but that it is still changing. Dead languages, like Latin, are stagnant, rules and meanings of words stay the same.
We can see the affect of a living language with our own English. Words are being added -googled, skyping, iPad- definitions are being changed -gay used to mean happy- and we are discovering new uses for words all the time, just as we are losing words all the time. And there are words that have multipal meanings depending on the context. Hot could mean burning, warm to the touch but it could also mean attractive, cool looking, fun or any other positive affectation. (Wait Hot can mean cool? Yup!)
Which brings me to an interesting little conundrum that I discovered while enjoying my daily dose of Forgotten English by Jeffrey Kacirk.
Dunch
“Deaf…I have no doubt that dunch is Anglo-Saxon…It ought not to be forgotten that many words are…being arrested by our etymologists in the present advancing age of investigation.” -James Jenning’s Dialect of Somersetshire, 1869
“Undeaf, to cure of deafness.” -Robert Hunter’s Encyclopaedic Dictionary, 1894
I hope that you are as confused as I am. Dunch apparently means deaf and undeaf at relatively the same time. But I suppose that is the fun of language…meanings change…usage shifts and we are left with words that have conflicting definition.
I hope you enjoyed this little post full of rather useless information. But, hey, you learned a new word!
While We're Paused... 
I object (I’m a lawyer, it’s what I do!) to the adjectives dead and stagnant to describe any language that’s still known, whose meaning we may still decipher. Sure, the rules of languages not in general use today are pretty well fixed — but better to use the descriptive word permanent than stagnant to describe that fixity. As C. S. Lewis said, the square of the hypotenuse of a right triangle has not gone moldy by continuing to equal the sum of the squares of the other sides.
Well, in my defense, Latin is considered a “dead” language. But I suppose you are right that “stagnant” is not the most positive of word choices.