I recall reading some years ago that the Celtic languages are more closely related to Latin and its daughter languages than they are to the Germanic languages. This may seem at first glance to be a bit counterintuitive, given the fact that the living Celtic languages are clustered in Northwestern Europe and fairly well surrounded (with the exception of Breton) by English.
However, in ancient times the Celtic peoples were close neighbors of the Romans. The history of Rome is littered with wars against the Celtic peoples to their north and west and it was largely the conquest of the Celtic tribes in places like modern day France that brought the Romans into contact with the Germanic peoples further north.
I recently embarked on an intensive study of Celtic history and myth. During my reading I came across a number of words that caught my interest for various reasons. The one that sticks with me the most is the Welsh word for book, llyfr. When I first encountered this word I immediately noticed its similarity to the French word for book, livre, but for some reason, I did not pursue the line of inquiry any further.
A few months later, I happened to stumble across the Irish equivalent, leabhar (pronounced, I am assured by a native Irish speaker, like “lao-wer”) and fireworks went off in my brain. I connected the Welsh, French and Irish words to the Spanish word for book, libro, and derivative forms such as the English library, which solidified the word in my mind.
When I say the “word” I don’t mean any of the words I have mentioned above, but rather the triliteral root of l-b/v/f-r. The different permutations of this “word” show the interrelatedness of and gradual transitions between different languages within the Indo-European language family and serve to drive home the point that the idea that languages are related is a literal, rather than a figurative, concept.
Ultimately, all of these words stem from the Indo-European root of leup- / leub- / leubh-, which is generally found in words having to do with things that are loose (such as lips), things that are peeled off (such as the bark of a tree or a leaf).
It gives me great joy to know that this primeval meaning, this base connection to the idea of something that is loose, a slice of something more substantial, has been carried through to modern times in such a consistent way in a series of related languages.