EEEEEEEEEEEEEEEEEE######MMM,,,,,,######

It wasn't a sound, exactly - but it was trying to get into your ears. FFFFFFSS######JJJJJJ###. It crackled and popped in poor, defenseless triangles across some impossible spectrum. But even if it couldn't be decoded into language, the killing intent was clear. This was an attack. The desire was to hurt. 

MMMMMM#####$$$$$$$$$$

The tone changed, shifting downwards. It was a prettier tone, soothing, pleading, offering - but it still hurt the ears. It was just at the wrong frequency - every word broadcast by the terrible space crab was scratching against a language this world no longer knew how to speak. And so, in the absence of a delusion of meaning conjured in a receptive brain, that underlying desire to inflict pain was clear. UUUUUUUU#####$$$$. It rotated through words and sounds, trying to find the ones that would cause its prey to do what it wanted.

BLLLLLLLLLLLLLLLL#######,,,,,,,

It did not seem particularly invested in this attack, in the same way that a poisonous cobra does not need to think about the pattern of eyes around its neck in order for them to strike fear. It had nothing to say to anyone - it was just a crab. But the ability to try and manipulate intelligent life through their language was the one evolutionary refinement that technological civilization had contributed to the crab's divine perfection, and the monster burned through spectrums trying to find the one that would cause its opponents to lower their guard.