What is the meaning of -m?

Used to form dependent verbal forms denoting simultaneous or sequential action from indicative forms.

Used to form (pro)nouns taking on the quality of the suffixed determiners, numbers, verbs and nouns.

Forms comparative adjectives.

Forms nouns from verbs.

my (first-person singular, single possession)

First-person singular personal suffix:

1. Definite forms of transitive verbs (followed by a linking vowel in indicative present/past and subjunctive moods; with no linking vowel in conditional mood).

   Definite forms of transitive verbs (followed by a linking vowel in indicative present/past and subjunctive moods; with no linking vowel in conditional mood).

   Indefinite forms of -ik verbs.

   Forming conjugated infinitives (here: “for me to do something”).

   Declined and postpositional forms of the first-person personal pronoun én (“I”).

   Added to a verb (or rarely to a noun) to form a noun. No longer productive in this sense.

   No longer productive in this sense.

   alternative form of -mo

   first-person singular suffix

   Forms verbal nouns of A III (hiatus) verbs

   Plural suffix (with m-declension nouns)

   and

   past-tense first-person singular suffix

   first-person singular suffix

   Evidential suffix, first-hand information. Indicates that the speaker has direct evidence/knowledge of some fact, having experienced it, seen it, heard it, etc.

   Used to mark an open-ended question; less formal than -taq.

   Post-vocalic form of -im.

   alternate form of first-person singular simple present tense copula conjugation suffix -um used after informal present continuous suffix -iyo

   Form of -im after a vowel.

   Source: wiktionary.org