<span>Stem changing verbs have spelling changes in all forms of present tense EXCEPT nosotros(as) & vosotros(as). Stem of verbs are the part of the infinitive that's left after dropping endings such as -ar, -er, or -ir. Pedir translated is "to ask or order". The way you'd put that in present is Yo - Pido. Tu - Pides. El, Ella, Ust. - Pide. Nosotros - Pedimos. Vosotros - Pedis. Ellos, Ellas, Uds. - Piden. Servir is the same way just replace the -ir with the correct change.</span>
