[lambainsaan]

Wait prepone is not an English word, what!?

I use it all the time.

[charcircuit]

I have never heard it or even seen it in my life.

[bigbillheck]

Me neither, but it's a perfectly cromulent construction.

[incrudible]

My thoughts exactly, it would embiggen our vocabulary.

[krona]

If you use it, then it is a word. If other people don't understand you, then that's your problem.

[rsynnott]

In English, which lacks the sort of central control that, say, French has, if people use it, it's a word. It's just a word that isn't commonly used in some dialects.

[bobsmooth]

It's a perfectly cromulent word.