Present tense

The present tense is formed as follows.

When the stem of a verb ends in  -d, -t, an "e" is added in the 2nd and 3rd person singular and in the 3rd person plural.

The same applies to verbs whose stem ends in a consonant + -m, -n. Exception: When an  -r precedes the -m or -n, like in verbs formen, wärmen, lernen, turnen.

When the stem of a verb ends in -er or -el , the "e" of the ending in the 1st and the 3rd person plural and in the polite form is deleted.

In addition, verbs whose stem ends in -el, usually lose the "e" of the stem of the 1st person singular.

When the verb stem ends in -s, -ß, -z or -x, the "s"  in the ending of the 2nd person singular is deleted.