This document discusses stem-changing verbs in Spanish. It provides examples of common stem-changing verbs like querer, jugar, and tener. It explains that the stem, or main part of the verb, changes its vowel sound in certain forms. For example, the "e" in querer changes to an "ie" in forms like "yo quiero." It also notes two verbs, empezar and venir, that are exceptions and do not stem change. Finally, it mentions that learning which verbs stem change will require memorization but offers reassurance there are only a few patterns to learn.