@MinMan1 I think a chatroom is probably the best analogy. The Lamia tap-speaking is mechanically similar to morse code in that the speaker is indistinguishable from another speaker. Every lamia, werewolf, and lizardman sound similar via taps. So if you imagine a chatroom without usernames associated that is how they speak. Very similar to how chat is many conversations and statements at once.
Having lived with the Lamia and communicated with them through this method for so long, the others converse through the same linguistic structure. In a way mirroring how we incorporate elements of our communication methods in our everyday speech.
It seems that to begin a conversation you address a particular statement with a question and this establishes who the dialogue is with. From there it relies on continued engagement, continuously identifying the speaking parties, or else it dies and goes back into the main pool.
I think that is what Kekoo and Kashoo mean by “You can choose whether to listen (or) not”. Meaning that he chooses if he wants to converse or not with any speaker from the pool by questioning or requesting them. It’s not a conversation demanding a personal response unlike our common way of speaking.