I have noticed that many of the humans who use this word have black plastic glasses on their faces.
These humans are all very careful. They do not only care about what words mean, but also how the letters in them look.
Letur-fræði means means "typography", but many of the people who speak Icelandic do not say "leturfræði". They think it is more töff to say "týpógrafía".
Because you are probably also a careful person (maybe you have black plastic glasses on your face, too) you have noticed that my people's language has letters in it that other languages have forgotten. Maybe you have seen them on my inter-nets.
They look like this: Þ, ð, æ and ö.
Maybe you think they all look strange, but Ð is the most töff, because it never appears in words as Ð, only as ð.
Many humans who are busy making letters for other humans to use in news-papers and on inter-nets do not know how to make an "Ð", because not many people need it. But a few weeks ago they all met in a building that my people built to listen to loud music and talk about important things in. And they talked about it, and now they know all about how to make an Ð.
(If you want to know more about that you can read what a clever human called Ðan Reynolds wrote about it on his inter-net.)