The Spanish correr, “to run” seems completely unrelated to the English horse. Looks can be deceiving.
Correr comes from the Latin for the same, currere. Currere, in turn, comes from the Proto-Indo-European root *kurs, which also means, “to run” — just like horse does! Both have the same common ancestor.
The weird thing is: how did the PIE *kurs turn into horse, they sound so different.
The explanation is that, in the Germanic languages like English, the k- sound turned into the h- sound. But in Spanish, the original k- sound remained, although usually written with a c-.
This explains many parallel words that have c- and h- sounds that map to each other between Spanish and English, like heart/corazon and head/cabeza.
The Spanish for “shirt”, Camisa, is a distant cousin of the English Heaven. How?
Both come from the same common ancestor, the Proto-Indo-European root *kem, meaning, “to cover.” This root evolved, via German, to the English heaven (that which covers us above) and it evolved, via Latin (and even the French chemise), to the Spanish camisa (that which covers our torso!).
But they sound so different. How can that be?
The answer is that the Indo-European sound k- transformed over time into the German and then English h- sound — which remaining the same (albeit with a c- spelling) in Latin and then Spanish. Thus the c- of camisa maps to the h- of heaven.
Other examples of this pattern include cornudo/horn and horse/correr.
Today’s is a good one!
The Spanish caro (simply, “expensive”) has a fun provenance: from the ancient (pre-Latin) Proto-Indo-European root karo- that meant… whore. Yes, the ancient word karo turned into the almost-as-ancient Latin word carus meaning “expensive,” from which we get the modern Spanish word caro, still meaning “expensive.”
So the prostitutes of the ancient world, apparently, weren’t cheap!
Interestingly, we can even see a linguistic connection between the words. The k- sound in Proto-Indo-European stayed the same sound as it evolved into Latin and then Spanish (although usually written with a c-); but as Proto-Indo-European evolved simultaneously into ancient German and then into English, that k- sound became the silent or almost-silent h- or wh-. Think when and cuando, for example. So, we can see therefore that the c‑r of caro maps to the wh‑r of whore.
The funniest part, however, is that the ancient Latin carus, for expensive, as Latin evolved into French, turned into the French… cher, for “dear”: in the sense of, “My dear friend!”. The exact opposite of a whore! Thus, in French, prostitute became expensive which became that which is dear to you!
The Spanish for “horn”, cuerno (and its variations, like the ever-present cornudo), and the English horn are both originally the same word in the ancient languages.
One of the most interesting sound shifts is the Indo-European “k-” sound remained the same into Latin and then Spanish (the Latin cornu for the same) but became an almost-silent “h-” in the Germanic languages.
Thus the c‑r-n in Spanish parallels exactly the h‑r-n in English.
There are lots of awesome and subtle examples of this pattern, such as Corazon/Heart.
The Indo-European root kaput, meaning “head”, led to words for the head in almost every western language, with no change.
The kaput turned into the almost-identical caput in Latin; and then that evolved, through very minor changes, to the almost-the-same cabeza in Spanish. The main sound shift is the p to b, but those are very clearly aligned signs that often swap.
Kaput, however, evolved into the German kopf — which then became the English head. How so?
The Germanic sound “k-”, as German evolved into English, generally became the “h-” sound in English. Take century/hundred or horn/cornudo or, my favorite, hemp/cannabis as other examples.
Thus, the c‑b(-z) of cabeza maps to the h‑d of head. In the English pattern of short, powerful words, the final sound was lost as well, to give us the simple, straightforward head.