Since animals with the celectial template get bumped up to Intelligence 3, does that mean they can speak? And if so, I imagine they speak Celestial, correct?
Yes, they should be able to understand at least one language (speaking requires body parts they may still lack), and by the book, that language is Common (because the rules say that's the default, and the rules don't specify anything different for celestial creatures). However, it makes a lot more sense, IMO, for it to be Celestial. You do, however, run into a problem trying to apply the same logic to fiendish creatures (because there are Abyssal and Infernal tongues, but no Fiendish language), but nothing that can't be handwaved.
I agree with vegepygmy. A creature with an intelligence of three should COMPREHEND common a little better than the avreage bear, but could not speak it (a bit like wookies). So I guess you could give it more complexe orders or even reason with it to some extent.
Ultradan
Thanks guys, this is most helpful. The particulars of why I ask is the line under summon monster that states: "If you can communicate with the creature, you can direct it...." I've got a new cleric PC who speaks Celestial as a bonus languages, and I got to thinking that if the celestial animals he summons are intelligent enough to speak (or as both of you point out, "understand") Celestial (or Common, though I'm dubious in that regard), then he should be able to direct them as described, or best of all, guide them as to when (or when not) to expend their daily smite evil attack.
On a related tangent. In your experience, who should run summoned creatures? The player of the summoning PC, or the DM?
In your experience, who should run summoned creatures? The player of the summoning PC, or the DM?
The player (with DM holding a power of veto, of course).