Remember that only verbs ending in -IR can have an e-i stem change.
Explanation
"Advertir" has an e-ie stem change.
The nosotros form never has a stem change.
Dormir has an o-ue stem change.
Querer has an e-ie stem change, except in the nosotros/vosotros forms!
Jugar has a u-ue stem change. Perder has an e-ie stem change.
Pedir has an e-ie stem change. Almorzar has an o-ue stem change.
Reir has an e-i stem change. Contar has an o-ue stem change.
The vosotros form never has a stem change.
"Entiendo" is the yo form and "entendemos" is the nosotros form.
"Dices" is the tú form and "decimos" is the nosotros form. "Decir" also has an irregular yo form (digo).