Throughout all of history alphabets have aided differing peoples around the world to document, and deliver messages. There are all kinds of ways to represent sound... from rhythm, to pitch, timbre, and even formants. Letters are a common way of representing sound in a purely visual form. Of course, you have to be initiated into that language to wield those symbols' powers.
1.) Choose a letter-form. Two studies work very well.
2.) Trace your two studies.
3.) Alter your letter-form in any number of ways using color, transposition, italicizations, remove serifs, add serifs, alter line quality, add negative or positive space.
4.) Conduct two final studies in large-format in different media. Try one in watercolor, and the other in oil pastel. You may also choose to use Susan Seddon Boulet's ink and oil pastel technique as outlined here and here in archived posts.