Forest gnomes have the following racial feature:
Speak with Small Beasts. Through sound and gestures, you may communicate simple ideas with Small or smaller beasts.
Like many words in English, "communicate" has different senses with differing definitions. In fact, the Oxford English Dictionary (OED) has 18 different senses for the word "communicate", with a separate definition for each sense. At issue is whether the "Speak with Small Beasts" feature is using the word "communicate" in the sense of one-way communication, or two-way communication of information. The former is verb sense #1 in the OED; the latter is verb sense #8.
The OED's sense 8 is "to impart, exchange, or share information or ideas with, by means of speech, writing, signals, etc... to be in mutual communication." This means "communicate" certainly can mean mutual exchange of information.
In reading definitions, one must be aware that the preposition paired with a word makes a difference in meaning. The sense above, sense 8, is the only one in the OED that specifies the preposition "with". In other words, the phrase "communicate with" has only this sense, according to OED. So, this would seem to mean that when the RAW mentions communicating "with" small beasts, it is in the sense of a mutual exchange of information.
However, one problem. Sense 8 is listed as intransitive, meaning it should not have a direct object. But the sentence in question, in RAW, has a direct object ("simple ideas") and thus is transitive. And all the OED's verb senses that are listed as transitive, describe one-way communication, e.g. sense 1, "to convey, express; to give an impression of, put across".
Which brings us to the following point: the sentence in RAW is bad English style, because it mixes a transitive object with the preposition "with", which breaks the OED specification of this word. On the one hand, if you say "communicate (something)" and you mean it to be a one-way communication, the next preposition should be "to", not "with". Conversely, if you pair "communicate" and "with" and you also want to specify what is being communicated, then you are supposed to introduce another preposition, such as "about."
RAW does neither of these, and thus creates an ambiguity between sense 1 and sense 8 of "communicate". To make this more clear, here are two slightly modified versions of the sentence, that would have left the matter entirely clear:
"you may communicate simple ideas to Small or smaller beasts" (clearly sense 1)
"you may communicate with Small or smaller beasts about simple ideas" (clearly sense 8)
RAW did neither of those, and sort of combined the two. So semantically, it is a bit of a mess.
So, finally, the question: Is there anything else in WOTC 5e materials that clarifies whether the communication mentioned in this rule is one-way or two-way? For example, is a forest gnome NPC depicted in a published adventure as having two-way communication with a squirrel by means of this feature? Because that would settle it. Is there anything like that? Or if not, then is the answer, "It's up to the DM"?
I noticed that this answer shares rules from 3.5e that clearly indicate a two-way communication for gnomes, but I am looking for an answer within 5e materials (if there is one).