"I am fast."

Translation: Je suis rapide.

[Chefie]

why not 'je suis vite'?

[Sitesurf]

"vite" is not an adjective but an adverb.

[inermes]

i'm sorry, i'm not expert, but in wordrefereces
http://www.wordreference.com/fren/vite
vite id an adjective too

[Sitesurf]

I know, but it is ugly French (why change an adverb into an adjective, when you have an available adjective?)

[Svun7]

Why do you say that? http://fr.wiktionary.org/wiki/vite says it is, which is taken from Dictionnaire de l’Académie française, huitième édition, 1932-1935

[Sitesurf]

We don't use it any more in modern French, we use "rapide", which is a true adjective.

[FrancisBuahin]

I think a language that doesn't 'grow', dies. Am I right if I say Le français vivant?

[Svun7]

That seems like more of a statement about awkwardness than correctness.

[Svun7]

So I decided to ask a couple French folks at work and they confirmed that they see "vite" as an adverbe and not an adjective. They consider it incorrect, as you mention.

[TheCtrlmas]

GOTTA GO FAST

[mike_stoltenberg]

J'ai la vitesse. ??

[Sitesurf]

Only if you mean "I have speed, you have endurance" (J'ai la vitesse, tu as l'endurance).