Model: fallen
Auxiliary: sein
Other forms: befallen
Irregular conjugation for ther verb "fallen" and its compounds: stem vowel mutation (umlaut) in singular form of the second and third person in Present tense ("du fällst").There is a vowel change in the stem of Present tense ("ich falle") and the stem of Preterite ("ich fiel") and the stem of Past Participle ("gefallen").
Präsens
Präteritum
Futur I
Perfekt
Plusquamperfekt
Futur II