What is the meaning of -ja?

You, ya.

alternative form of a

Used to form agent nouns from verbs: -er

First infinitive marker.

alternative form of -a

-er (used to form agent nouns from verbs)

forms a tag question, requesting confirmation: right?

expresses complaint about the term it attaches to

-er; appended to verbal stems to form agent nouns, especially human ones

derives various adverbs

Forms agent nouns, especially human ones; -er

romanization of -𐌾𐌰

Possessive (and genitive) suffix:

1. his, her, its …

   his, her, its …

   …-'s, of … (third-person singular, single possession)

   …-s’, of …-s (third-person plural, single possession)

   … ago (referring to a preceding point in time considered as an instant)

   for … (referring to some duration that precedes the point of time in question)

   of …, out of …

   Forms the definite third-person singular present tense of back-vowel verbs (with identical or different assimilation rules depending on the ending of the stem—see the tables below):

   1. in indicative mood

      in indicative mood

      in subjunctive (imperative) mood

      forms regular 0-stem weak verbs

      2. forms causative verbs from (mostly) strong verbs

         forms causative verbs from (mostly) strong verbs

         forms verbs from nouns

         forms factitive verbs from adjectives and nouns

         alternative form of -a (feminine, plural, or singulative ending), used with stems ending in -i, -j

         alternative form of -i (1st-person singular non-verbal pronominal suffix), used with stems ending in vowels or diphthongs.

         Suffix appended to words to create a masculine noun, usually denoting a profession, performer or a feature, usually negative.

         Source: wiktionary.org