Our language is ever at risk of becoming something knotty, chaotic, and superfluous. We define concepts - but suppose we define too many or not enough? How should we know what "too many" and "not enough" even are? We might make critical those concepts that we most need to do away with. We might create entire studies, entire subjects, that we devote our lives to that simply do not matter.
Language is human.
We must return to phenomena as a fixed point to keep from losing our minds. This is not to say that we must keep language simple or that language must slavishly proceed from what we observe, but it is to say that there is something outside of language that language relates to.
Perhaps we like our language to be simple, we must wonder what we want it to be simple in relation to? And the answer is phenomena. Or suppose we want our language to be specific. Specific according to what? According to how much we can see. Phenomena keeps us from getting trapped by the words that proceed from our own mouths.