Malami ya koya mana cewa bambancin kuɗi bai kamata ya hana girmamawa ba.

not

Breakdown of Malami ya koya mana cewa bambancin kuɗi bai kamata ya hana girmamawa ba.

• kudi: the money
• malami: the teacher
• mu: us

Questions & Answers about Malami ya koya mana cewa bambancin kuɗi bai kamata ya hana girmamawa ba.

What does ya express in Malami ya koya mana? Is it just past tense?

Ya is the 3rd person masculine singular subject pronoun plus a perfective marker.
In ya koya, it marks that the action “teach” is completed, so in this context it corresponds to a simple past in English: “The teacher taught us…”.
Hausa always needs this kind of subject marker in a finite clause; you cannot just say Malami koya mana without ya.

What exactly is mana, and how is it different from mu or muna?

Mana is an object pronoun meaning “to us / for us”.
So ya koya mana = “he taught (it) to us.”

• mu = independent pronoun “we / us” (e.g. mu ne, mu muna zuwa).
• muna = “we are …ing” (1st person plural imperfective marker).
• mana is specifically an enclitic indirect object: ga mu → mana (“to us”).

What does cewa do in this sentence, and can it be left out like English “that”?