I'm going to chime in belatedly and say that most actors study acting from a script - on stage, it's all dialog so the producer/director can place their vision on top of it.
At the low budget level, most of the script's I've seen for short films are all dialog... supporting the falsehood that acting is speaking dialog. The most common note in the margin of a script that I've ever written is "TMD" -- too much dialog. Only Kevin Smith can get away with writing like Kevin Smith - grumbly note to up and coming script writers! More action blocks in your script (at least, a 50/50 balance, better yet 75/25 action/dialog). Dialog should never reveal the plot directly, but be something the character would say while immersed in the plot - otherwise, you can write for radio).
That said, actors are taught that the written word is EVERYTHING THAT MATTERS in every way... I hate that attitude. The word informs the audience and the actor of the plot, plot and story should always be considered more important than the words - and if the words are wrong, the director should be ok changing them on the spot (and know the script well enough that the changes won't ripple problems through other parts of the script).
As always, the problem isn't the actor, it's the writer/directors who have been feeding them the line that their "art" is unchangeable and their "art" only contains the words, no hints of action or emotion. If you want an example, pickup any copy of a monologues book that actors use as excercises... there are absolutely no stage directions in them whatsoever. Actors are trapped by words.
Have them run a scene without any dialog if you run into that problem, let them experience the moment silently, then add the dialog on top of that. The director is responsible for the outcome; end statement.