It's all in the name
Sprokið means 'The language' or 'The tongue' in Icelandic. The word is actually extinct, was in use in the 18th century or so, but it is of the same origin as språk, sprog, sprack etc. Thought I'd use an extinct word of (transparent) Germanic origin to symbolise my interest in etymology and language relations and all that.

Speaking of etymology, Íslensk orðsifjabók (there's even a sample on that page, click the link that says 299!) is quickly becoming one of my favorites. Strangely enough, orðsifjar is not an entry, but perhaps it is transparent enough: orð is 'word' and sifjar is derived from Gothic sibja, Old English sibb, Saxon sibbia, which probably is the root for the modern English word sibling? Means relation, or connection, usually in the context of marriage. In this case, orðsifjar would then mean something like "the family relations of words", which is cute. Not translating quite as directly between the languages we get 'etymology'. The genitive case is orðsifja, and added to bók, 'book' you get the title, "book of etymology".

The whole book is a wonderful reference to roots, old and new, in languages, closely and distantly related, alive and extinct.