The French verb étudier is not an irregular verb, and follows the normal rules of conjugation for an -er verb as follows:
Take off the -er and add
(je) -e
(tu) -es
(il/elle/on) -e
(nous) -ons
(vous) -ez
(ils/elles) -ent
Therefore the conjugations for étudier are:
J'étudie
Tu étudies
Il/elle/on étudie
Nous étudions
Vous étudiez
Ils/elles étudient
Hope this helps :)
