Pronouns x Pronounce

The other day I was talking with my teacher:

J: I would like to talk to you about pronouns. 

He replied:

M: pronunciation. 

I didn't understand why he said that, and we started talking about other things. After a while, he asked:

M: What do you want to know about pronunciation?

I didn't understand why he said that, and replied:

J: I don't want to talk about pronunciation, I want to talk about pronouns.

He replied:

M: Pronounce. 

I said:

J: Pronouns.

After three times doing this, I said:

J: I want to talk about pronouns, for example, I, you, etc.

M: Ahhh, I thought you were saying pronounce. The way that you were saying it sounded like "pronounce". 

Before this day, I didn't notice that these words were so similar.