The Spanish verb entender (to understand) is irregular since the stem changes in some forms El Presente and the endings are irregular as well.
|él / ella / Ud.||entiende|
|vosotros / vosotras||entendéis|
|ellos / ellas / Uds.||entienden|
Notice how the first vowel -e- in the stem becomes -ie- except for the nosotros and vosotros forms.
Read and listen to these examples:
List of Common Spanish stem-changing (e > ie) verbs in the present tense