Look at the conjugations of a few stem-changing verbs. Identify the conjugations that change stem and the ones that don’t. Sometimes these stem-changing verbs are called ‘boot verbs’. Can you think of why?
yo juego nosotros jugamos
tú juegas vosotros jugais
él/ella/ud. Juega ellos/as/uds juegan
Because if you draw a diagram of the yo,tú,etc. And then make a bubble around the ones that change it looks like a boot. Hence the name boot verbs, only the ones in the bubble change. Hope I didn't confuse you.