Mine is 2, mostly two words but sometimes more. I have been doing a lot of experimental work with multi-word input. In the early part of the game, you have to gather information using commands like ASK GANDALF ABOUT FRODO or READ ABOUT THE RING IN THE BOOK. That might sound like a lot of typing, so, where the context allows it, I've also allowed for a shorter form like ASK ABOUT FRODO or READ ABOUT RING.
I've also started implementing implicit actions, whereby if you only type the verb and the noun and an indirect object is required, but it can be implied from the context, then I allow for it. For example:
> GIVE FISH
(to Gollum)
Gollum gobbles down the fish, bones and all.
This is probably a bit bleeding edge for Adventuron, but it's what I'm used to nowadays and will (hopefully) make it more intuitive for beginners.