My party has two Forest Gnomes and a Firbolg and they want to use their racial features to secretly communicate.
Forest Gnomes have
Speak with Small Beasts: Through sound and gestures, you may
communicate simple ideas with Small or smaller beasts.
Firbolg's have:
Speech of Beast and Leaf: You have the ability to communicate in a
limited manner with beasts and plants. They can understand the meaning
of your words, though you have no special ability to understand them in return. You have advantage on all Charisma checks made to influence them.
Speak with Animals reads:
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. You might be
able to persuade a beast to perform a small favor for you, at the GM’s
discretion.
- Through their shared knowledge of Speak with Small Beasts can Forest Gnomes communicate simple ideas to each other?
- Can Forest Gnomes understand a Firbolg speaking to them as it would a small animal even though it could not respond in turn.
- Would a Speak With Animals user be able to eavesdrop on either?
Best Answer
Only if they have a friendly animal
This works, but only if they include an actual small beast in their conversation. None of the abilities involved indicate a language or other static kind of communication that could be attempted without an actual plant or animal to interact with.
That said, if any small animal is included in the conversation (for example the mouse from the Urchin background, a befriended wild animal, or a 2 cp chicken), it works more or less exactly as you describe. The Firbolg can talk to the chicken, who can tell the gnomes what the firbolg said. The gnomes can talk to the chicken, who can transmit messages between them. Someone affected by speak with animals can understand anything the chicken says to the gnomes.
Ruling that these abilities confer languages is not a bad idea
Animals in 5e don't have languages. In past editions, the ability of gnomes to speak with animals often implied that they did:
3.5: forest gnomes have "a simple language that enables them to communicate on a very basic level with forest animals"
AD&D: surface gnomes speak "the languages of burrowing mammals"
If you want to run a game with previous edition setting material, or if you want your world to have this sort of animal communication, it makes sense to have animals have languages and rule that these abilities work via that mechanism and thus are interintelligible. This is, of course, not part of the RAW but it also isn't contrary to the RAW and consequently you won't have any mechanical problems you didn't already have when ruling this way.