Perejil and its English version parsley sound very different. But they are, actually, etymologically the same word.
They sound different because often the ‑s- and ‑sh- sounds in Spanish turned into the letter ‑j- with the Arabic throat clearing sound as a pronunciation. Thus, the p‑r-j‑l of perejil maps exactly to the p‑r-s‑l of parsley.
“Fig” comes from the Latin “Ficus” — obvious enough!
But, curiously, the Spanish word is “Higado”. Huh?
This is just a simple example of the Initial F to H pattern. In lots of Latin words, the first F became an H when Latin evolved into Spanish. Think fact/hecho or hablar/fable.
An easy way to figure out what an H- word in Spanish is: change the initial H to an F and see what English word sounds similar.
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 Spanish hambre, for “hunger”, makes sense if you know two different patterns.
Firstly, the initial f‑to‑h pattern: words that began with an f- then a vowel in Latin tended to have the f- turned into an h- when Spanish evolved into Latin. Huir and Fugitive is another example of that pattern.
Secondly, the mn-to-mbr pattern: when the letters in Latin “m” and “n” appear together, often separated by a vowel, they usually became “mbr” as a unit in Spanish.
Thus the f‑m-n of famine maps directly to the h‑m-b‑r of hambre.
The English fact comes from the Latin factum, meaning “something that happened.” It is thus an exact cognate to the Spanish hacer, meaning “to make.” How?
The root of both is the Latin facere, meaning “to do.” Fact, and the Latin factum, is just the same word in a different tense.
The Latin facere turned into the Spanish hacer, although they superficially sound different. Their relation becomes obvious once we remember that Latin words that began with an initial f- almost always turned into an initial h- when Latin evolved into Spanish.
Therefore the f‑c-r of facere maps exactly to the h‑c-r of hacer.
This pattern explains many words such as hierro/ferrari, hervir/fever, huir/fugitive, hoja/foliage!