According to the quotes by Griffin on another thread:
Griff and bucket has a discussion and theorizes about how they think maybe the monsters know what the colonists know because they eat them and gain their knowledge or something, but again, that’s just a theory Bucket has. Griff pretty much responds with “Now that you mention it though…” or something, but that’s all I’ve heard.
Therefore, it is now known that the monsters are able to assimilate and also demonstrate the intellectual capacity to comprehend the information and knowledge of the colonists in one way or another.
A high intelligence requires a large frontal lobe, in order to understand the verbal and semantic information of the colonists’ words, language and speech.
What does this mean?
Above: It means that monsters have a powerfully developed frontal lobe, that is possibly as powerful, if not more, than humans.
What does a large frontal lobe entail?
Above: The Broca’s area is a part of the frontal lobe, that is responsible for speech and verbal comprehension. The motor cortex for speech production is also in the frontal lobe, responsible for speech articulation. Wernicke’s area is likewise important for speech reproduction, and is abnormally developed in the brains of male parrots and songbirds, as seen below:
What does this all mean?
This means that monsters have all the semantic and speech production capabilities that enable them to understand and reproduce human speech, and to also articulate them. Which means, that they have every faculty, on par with humans, parrots, songbirds and hummingbirds, to be able to reproduce music vocally.
What does that mean then?
Simple. Monsters should be able to sing, just like human beings.
Just a disclaimer, when I said “why monsters should be able to sing” in the thread title, I meant that they have the capacity to sing; they “can” sing, but I am not saying that they normatively “ought to” be able to sing.