Pluma, Spanish for “feather”, sounds nothing like the English feather.
But it is a cousin to the English fleece.
Both come from the same Indo-European root *pleus-, which meant “feather” or to “pluck.”
But they sound so different! That is because the Indo-European p- sound stayed the same into Latin then Spanish, but changed into a f- in the Germanic branch (including English).
Thus the p-l of pluma maps to the f-l of fleece.
The English foot comes from the Indo-European root *ped. Think pedal.
Interestingly, the “p” sound consistently transformed into an “f” in the Germanic languages — but remained a “p” in the Latinate languages.
This is why, foot is equivalent to pie.
Other examples of this pattern include father and padre, and the English far is from the same root as the Latin per.
It is both surprising and funny that in Spanish, a Flea Market is translated to be, literally, exactly the same: Mercado de Pulgas.
But it is even more surprising (although probably less funny) that flea and its Spanish translation, pulga, are close cousins – despite the different sounds.
Both derive from the Indo-European *plou. To understand this transformation, we should remember that the Indo-European p- sounds stayed the same in Latin (and thus Spanish) but became an f- sound in German (and thus English).
Therefore, the f-l of flea maps exactly to the p-l of pulga!