Your mom’s first language has words for love that don’t translate. You understood them anyway. That’s fluency too.

Understanding runs wider than vocabulary. There are words you could not spell or define that you have always known the meaning of, because you learned them from tone and repetition in your own kitchen. That counts as knowing a language, even though no test would ever record it.

Ask her what one of those words means to her and where she first heard it. Write it down the way she says it, misspelled if necessary. Try using it back at her once this week and watch what happens to her face.