en_tn/1co/14/15.md

What am I to do?

Paul is introducing his conclusion. AT: "This is what I will do." (See: rc://en/ta/man/translate/figs-rquestion)

pray with my spirit ... pray with my mind ... sing with my spirit ... sing with my mind

Prayers and songs must be in a language that the people present can understand.

with my mind

"with words that I understand"