Change One's Tune

So to day we're going to be looking at some idioms that are related to music. So the first one is, change one's tune. How did you say that? Soyes, i say tune. In the when you have a t and a u together, we tend to make it more like a che sound. And why do we say this? Like wyt what is a tune? A tune is actually another word for a song,. Or, i love this tune. That kind of comes from music as well, because you would like tuning a piano, or you tune a guitar, right when it's out of tune exactly.