Ducha, Spanish for “shower”, sounds unrelated to the English for the same. But it does have a less obvious cousin in English: duct; both do conduct water, towards a particular direction!
And yes, from the same root we also get, via French, douche, as in, douchebag.
Duct and Ducha both come the same Latin root, ductus, “leading”. More on that one another day.
The transformation happened due to the always-fun pattern of the -ct- words in Latin turning into -ch- words in Spanish. Thus, the d-ct in Latin and English maps almost exactly to the d-ch in Spanish.
The Latin for “eight” is Octo, from which we get the English Octagon.
Since most Latin words with a -ct- sound, like Octo, had the -ct- turn into a -ch- as the language evolved into Spanish, it is no surprise that eight in Spanish is ocho.
This same pattern manifests itself in noche/nocturnal, leche/lactose, and is one of our favorite patterns here at ForNerds!
The law and the good, in European languages, are associated with straight lines; the bad with the crooked. Think about the word crooked itself, literally! Or about right/rectangle, or the Greek ortho– for straight, hence, orthodox as well as orthodontics.
This is why it makes sense that Derecho — Spanish for straight and also for law — comes from the same Latin root that gives us direct.
The “ct” in the original direct turned into a “ch” in Spanish, in the usual pattern of “ct” turning into “ch” as Latin grew into Spanish.
The Spanish for “night”, noche, is related (via the common Latin ancestor) nocturnal.
Here’s the interesting part: the Latin sound “ct” consistently changed to the “ch” sound in Spanish. Think “lactose” and “leche”, or “octagon” and “ocho”. And this is another example of that pattern: the “ct” in “nocturnal” is the same as the “ch” in “noche”!
The Spanish hechizo (“spell”; nothing to do with the letters in words, but what a witch casts on you!) comes from the Latin facticius (“made by art”; “artificial” — indeed, that which is artificial is just something not occurring naturally but instead made by art!).
But how did artificial change to mean “spell”? Think about it this way: casting a spell goes against nature — it’s what the wicked, crazy and profoundly unnatural woman does! Think of the three weird sisters in Macbeth, and how they unnaturally stir up all the elements!
From hechizo (more specifically, from it’s Portuguese twin cognate, feitiço), we get the English fetish. How? Well, you have a fetish when the recipient casts a spell on you to become obsessed with the object of your fetish, right? Enough said!
That root facticius turned into hechizo by changing via two common patterns: the initial F in Latin tended to turn into an H as Latin turned into Spanish (compare fig and higo, or fume and humo!) and the -ct- tended to change to a -ch- (compare noche and noctural; or ocho and octagon). Thus the h-ch of hechizo maps to the f-sh of fetish.