An interesting grammar note from a book Iā€™ve been reading on Proto-Indo-European: Indo-European verbs require grammatical markers showing tense (past, present, future, etc.) and number (singular, plural, occasionally dual), but Hopi verbs require markers indicating whether you saw it yourself, heard about it from someone else, or consider it to be a truth. This is surely somewhat of an oversimplification, but even so, still pretty cool.