Language learning is demanding
Humans are generally professionals of a language. They have been using one (or several depending on the person) language every day since when they were babies. If one has a career of mathematics of the same level of experience, they must no doubt be called at least a professional, if not a genius. Mathematics at a professional level is hard to acquire. So this could be a story that indicates that a foreign language at the native-level fluency and understanding is hard to acquire.