Learn a few words of another language and you learn that people slice up the world differently.

Languages are not codes for one shared set of ideas. One has a single word for a feeling yours needs a sentence to describe; one divides family or color along lines yours ignores. Running into that does something small and permanent: it shows the categories you think in were handed to you, not discovered.

Learn ten words in a language someone you know speaks, and ask them for one that does not translate cleanly. The answer is usually more interesting than the vocabulary. You can do this in a lunch period.