In ancient times, manuscripts told would-be magicians that the gods like to be addressed in the oldest language that was used to worship them, since it showed the mortal man imitate immortality by length of time. (Meaning that theory works only for goetics, or theurgy.) Patricia C. Wrede had her magicians say that it was prevent the power from overflowing uncontrollably; it was necessarily NOT the magician's native tongue. (That one required suspension of disbelief on my part.) Poul Anderson had a character observe that by the Law of Similarity, extraordinary effects require extraordinary langue.
But there I was, innocently plotting along on a story, where two characters are discussing a specialized language, and one discusses how you don't want to use it in magic because it lacks the symbolic weight of meaning. In ordinary every day language, terms like "horse" or "rose" or "weight" pick up the symbolic associations. I mean, the other character usefully talked about how fancy handwriting helps, but -- I don't think I can really world-build a magic that uses the plainest and most commonplace language possible. If only for the difficulty in explaining what's the difference between spells and ordinary conversation!
I may end up excising the conservation, if a balancing act is not possible.