conjugation.present.stem-e-ie
Stem change e → ie (pensar, querer, sentir)
The stressed stem vowel e becomes ie in yo, tú, él/ella/usted, and ellos/ellas/ustedes — never in nosotros, vosotros, or vos.
conjugationA1, A2standardinternally_reviewedv1.0.0
Explanation
In many verbs, the last e of the stem turns into ie whenever that syllable carries the stress: pensar → pienso, piensas, piensa, piensan — but pensamos, pensáis, because there the stress falls on the ending.
This 'boot' pattern (the four changing forms draw a boot shape in a conjugation table) applies across -ar, -er, and -ir verbs: querer → quiero, sentir → siento, empezar → empiezo.
Vos forms never diphthongize, because vos endings are stressed: vos pensás, vos querés, vos sentís. For -ir verbs of this family, the e also raises to i elsewhere (preterite third person, gerund, some subjunctive forms) — see the third-person stem change rule.
Examples
I think about you.
Region: global
Do you want to come with us?
Region: global
We think the same.
Region: global