Some verbs show a few peculiarities in their conjugation:
verb stem ends in –t / –d or consonant + n/m: an extra ‘e’ is added to the second and third person singular and second person plural to make pronunciation easier
verb stem ends in –s / –ß / –z: second person singular ends in -t
verbs that end in -eln or –ern: the first and third person plural end in –n instead of –en