Verbs with a stem ending in consonant + m

In the present tense, German verbs whose infinitive stem ends in consonant + m equally:

 

add -est and not -st in the "du" form

add -et and not -t in the "er/sie/es" form

add -et and not -t in the "ihr" form

 

Normal present tense endings are applied however:

 

if the -m in the stem of the verb follows l or r i.e. in verbs such as "verfilmen" (to film) or "stürmen" (to storm)

if the -m in the stem of the verb follows another m i.e. in verbs such as "summen" (to hum)

if the -m in the stem of the verb is preceded by a vowel i.e. in verbs such as "reimen" (to rhyme) or "rämen" (to clear away)