verb (used without object), par·took [pahr-took], par·tak·en, par·tak·ing. to take or have a part or share along with others; participate (usually followed by in): He won't partake in the victory celebration. to receive, take, or have a share or portion (usually followed by of): to partake of a meal.

Is partake proper English?

No, it isn't. And what is proper? I think "participate in" would be a better fit in your example sentence. "Partake" can be used as a substitute for "take part in", as in your sentence, but it is more commonly used to mean "take part of", as in food or drink.

Is it partake or partaken?

Partook is the past tense of partake.