TRILL

Trill or "trino" in Italian is a way of playing two notes really fast, to give the effect of a bird singing. They uses this a lot for flutes or piccolos and it sounds really nice. You can also use it in any instrument like piano or violin. It's a tiny curvy line above the notes like this:

You play the note below to the written note. Listen to the video Music Theory Level 8 and you will understand. If you have a Do in the paper, you will have to play Si and Do, and if you have a Sol you play Fa and Sol, always the note below to the written note