This pattern of present tense formation also applies to the German verb "wissen" (to know). It also:
has a zero ending on the "er/sie/es" form of the verb, i.e. there is no final -t
has a zero ending on the "ich" form of the verb, i.e. there is no final -e
applies the change to the stem vowel to the "ich" form of the verb, as well as to the "du" and "er/sie/es" forms.
