The Spanish pudrir, “to rot,” has a surprising connection to the English, foul, a word meaning the same but sadly very underused these days — although still when quoting Macbeth: fair is foul and foul is fair!
Both come from the same Indo-European root *pu, meaning, “to rot.”
But the English one sounds so different because, in the Germanic branch of Indo-European, the p- sound turned into the f- sound. But now in the Latin branch.
Thus the initial f+vowel of foul maps to the initial f+vowel of pudrir.
From the same root are more fun words including defile, putrid, and pus. What wonderful imagery!
The Spanish pegar (“to paste”) comes from the Latin pix, meaning “tar.” That makes sense: “paste” looks like just a more diluated “tar.”
But pix itself comes from the Proto-Indo-European root pei(e), which meant, fat — think of animal fat, for example. It makes sense that this word evolved into a word meaning “tar”: that’s a bit what animal fat looks like.
From this same root pei(e), we get a few notable English words:
The Spanish for “foam”, espuma, comes from the Latin for the same: spuma. And this Latin comes from the Proto-Indo-European root *(s)poi-moi from which we also get the English… foam.
How so? Because the PIE root p- very consistently became an f- as it evolved into German then English, but this transformation never happened when it became Latin and then Spanish. Note words like foot/pie and father/padre.
Thus the f-m of foam maps to the (s)-p-m of espuma very clearly!
The relation between “five” in Spanish (cinco) and English is one of the more surprising relationships: they are indeed direct second cousins!
Both come from the same Proto-Indo-European root, *penkwe, meaning the same, five. (The greek for five also comes from the same: think about pentagon, for example).
The interesting part is this: the p- sound in Proto-Indo-European evolved into the Germanic and then English f- sound. Think about father and padre, for example or foot and pie. Five and cinco follow this pattern too, but in a more subtle way.
The Proto-Indo-European for the same, *penkwe, evolved into the Latin word for “five”: quinque. The qu- was pronounced in a hard way like a k- and then, as Latin evolved into Spanish, the k- was softened into the soft c- in cinco. So p- to k- to c-. You can see it through the similar sounds.
Indeed, the pattern is most obvious in the repetition of the sounds in both works cin-co as the c/k sound twice, at the start of each syllable. And the fi-ve as the f- sound (and its closely related, usually identical and often interchangeable sound of v-) at the start of each of its syllables as well.
Father is one of the most basic words in every language and a traceable pattern throughout the Indo-European languages.
The original PIE sound “p-” changed in all the Germanic languages to “f-“. This is referred to as “Grimm’s Law”, from the fairy-tale fabulist who first noted this pattern.
In the Latin languages such as Spanish, the original “p-” sound was preserved. Thus, the Spanish padre’s p-d-r root maps to the English father’s f-th-r root.