Author's Notes:

Letter 23: Here.

Also, it occurs to me that the chapter title might be a bit confusing, or I might not be as clever as I think I am. 1 / 2.5 = 0.4

To my faithful student, Twilight Sparkle,

Twilight, you have a lovely singing voice but that does not mean that you should skip out on the time and effort needed to train that voice in order to match reality to theory, but I am pleased you are trying new things and hobbies. I do understand the desire to pursue more relevant interests, however, and I assure you that at least you sound pleasant enough during a heart-song.

Your loving mentor,
Princess Celestia

PS. She is a mare of many talents.