Where does “-iitta” come from?

-iitta (Finnish) comes from Latin -ītēs, from Ancient Greek -ῑ́της, from Biblical Hebrew אֶפְרָיִם.

Ancestry of “-iitta”, step by step

Step	Language	Word	Meaning
1	Latin	-ītēs	adjective-forming suffix, especially of nominalized adjectives identifying groups of people as "those belonging to"
2	Ancient Greek	-ῑ́της	belonging to; member of; member of a group
3	Biblical Hebrew	אֶפְרָיִם	—