Typography is much more complicated than just words on a page. It is the form, the feel and the beauty of each simple character in any language. It is the art of the written language and can be just as beautiful and ugly as any other kind of art.
Anatomy of a letter
Cap height is the height of the letters.
X-height is the height of a lowercase x. It’s the most commonly measure lowercase letter.
The descender height is the length that letters like a g descend below the baseline.
The stem of a letter is similar to that of a plant. It’s the body of a letter.
A ligature happens when two letters are inappropriately touching.
A bowl is a closed, but rounded stroke. Please mind the gap.
Families of type
There are three basic styles of types. The first is serif which has little tails on the bases of a lot of the letters. An example is Times New Roman, Minion Pro or Baskerville
The next is San serif which is without the little tails. An example is Helvetia, Arial or Gotham.
The last is decorative which can be anything that isn’t easily classified in serif or san serif. An example is the type used on wedding invitations. Be careful with decorative type. It’s terribly overused and often difficult to read.