The Spanish celoso and the English for the same, jealousy, come from the same Greek root: zelos.

But how did this happen? They should so different!

The answer is that the Latin (and Greek) words with a -ch- sound and variations (like -sh-, the soft -j-, -z-, etc) usually turned into the hard, guttural, throat-clearing -j- sound in Spanish. Think about sherry and jerez, for example, or quash and quejar, or soap and jabón.

Thus, the c-l-s of celoso maps to the j-l-s of jealous.

Curiously, the ancient Greek form — zelos — meant jealousy, but in a more positive sense of enthusiasm and friendly rivalry. In a word: zeal — which also comes from the same root!

One of our favorite patterns of sound change between English and Spanish is the sh/j shift: under the influence of arabic, many words that had a “s” or “sh” or “sy” or “ch” sound in Latin, started to be pronounced with the throat-clearing sound and written with a “j”. See sherry/jerez and chess/ajedrez or syrup/jarabe, for example.

Another example of this pattern is the Spanish word for “juice”, jugo. It comes from the Latin succus meaning, “juice” (particularly sap, or juice from plants).

From this Latin root succus we also get the English… suck.

Yes, if it sucks — it is juicy! Literally!

We can see the mapping in the s-c to j-g mapping. The “c” and “g” sounds are similar and often interchanged.

Interestingly, in Spain they do not say jugo to mean “juice”; instead, they say… suco. Suco, funnily enough, also comes from the same root of succus. It is just the variation that never underwent the arabic “j” transformation.

From the same root we also get the English succulent, although we do not get the superficially similar English juice, which comes from the Latin ius, meaning, “sauce.”