Speak With Animals 5e Monstrosity
So speak with animals wont work.
Speak with animals 5e monstrosity. Because owlbear is Large monstrosity not animal. The Speak With Animals spell probably taps into some primal natural language. On casting speak with animals the caster could speak with animals or to be more precise gain answers when they posed them questions.
However getting easy advantage on your attacks while transformed is an amazing option to have. It was one of the spells available from the Balance of Belaros a holy relic of Tyr. You can safely kill an owlbear from afar with ranged weapons spells or.
Are just not Beasts any. Speak with animals 5e barbarian. A unicorn is.
Anything beast-like that is unusually powerful or has magical abilities like a griffon is going to be a monstrosity or something else. You can totally train an owlbear if you get to it early enough but being a magical abomination it lacks the connection to. The creature possesses additional hit points equal to your Charisma modifier.
Moreover when the target speaks any creature that knows at least one language and can hear the target understands what it says. If you want Hold Person to work on it its a humanoid. That granularity is gone in 5E and as stated Unicorns Griffons etc.
I think its fine to explain all this maybe with a nature or arcana check because the characters. Rules as written Owlbears are monstrosities not beasts. This spell grants the creature you touch the ability to understand any spoken language it hears.