Yet in the church - In the Christian assembly. The word “church” does not refer to the “edifice” where Christians worshipped, but to the organized body of Christians.
I had rather ... - It is probable that in the Christian assembly, usually, there were few who understood foreign languages. Paul, therefore, would not speak in a foreign language when its only use would be mere display.
With my understanding - So as to be intelligible to others; so that I might understand it, and so that at the same time others might be benefitted.