Can a player character understand the Giant Owl language when using abilities that allow communication with beasts?

Question

Does the speak with animals spell (Basic Rules, pg. 277) or the circle of shepherds druid subclass feature speech of the woods (XGtE, pg. 23) let a player understand Giant Owl the language?

I'm sure a player would be able to communicate with a Giant Owl with said spells & features, Giant Owls understand common for what that's worth, but I want to know if players can conceivably listen in on a conversation between two Giant Owls speaking their native language using these abilities.

Is there some innate property to languages which would exclude their comprehension from these abilities? My instinct is the Comprehend Languages spell would let players understand Giant Owl the language but not a mundane Owl. Whereas speak with animals would do the inverse, or partly the inverse in that they can communicate in mundane owl with a Giant Owl but not in Giant Owl with a Giant Owl.

Answer 1

These features do not explicitly interact with any languages.

These features, speak with animals and Speech of the Woods, do what their descriptions say they do. That is, if they interacted with a particular known language, that interaction would be explained in the description. There is just nothing to indicate that a creature knowing a bestial language changes how these features work when communicating with the creature. If you don't know Giant Owl, and a giant owl speaks to you in Giant Owl, you understand the owl in the manner described in whichever feature you are using:

You gain the ability to comprehend and verbally communicate with beasts for the duration. The knowledge and awareness of many beasts is limited by their intelligence, but at minimum, beasts can give you information about nearby locations and monsters, including whatever they can perceive or have perceived within the past day.

-speak with animals

you gain the ability to decipher their noises and motions. Most beasts lack the intelligence to convey or understand sophisticated concepts, but a friendly beast could relay what it has seen or heard in the recent past.

-Speech of the Woods

However, a DM might rule that an intelligent giant owl may be able to communicate more clearly.

These features leave a lot up to the DM, stating that the communication is limited by the target's intelligence. So while the features don't explicitly interact with the Giant Owl language, a giant owl is considerably more intelligent (INT 8) than a typical owl (INT 2), so it seems entirely reasonable for a DM to allow relatively complex communication with a giant owl.