I was wondering why certain slavic languages have regularly in the verb conjugation the ending -m in the first person singular and others have -u? Slovene: govorim vs Russian: говорю And why there are exceptions in some basic verbs, where occurs the -m in the languages where the -u is the standard rule and there occurs the -u, where the -m is the general rule. Examples: In BCS the -m ending is regular, but for the verbs htjeti and moći, you have -ja hoću -ja mogu On the other hand in Russian the -u ending is regular, while the -m ending occur in the verbs дать есть я дам я ем If I remember correctly the same happens in Czech and Slovak. In Slovene that doesn't occur though. Is it maybe because in proto slavic there where two endings for the first person singular depending on the conjugation pattern?