It’s true. English and the main Spain version of Spanish are two of the few languages in the world which have the sound. Even most Latin American versions of Spanish (maybe all?) do not have it.
In "distinción" spanish, the classic pair is the word for house and for hunt - "casa" and "caza" respectively. If you pronounce them the same (with an S sound), you're a Seseo speaker like (most) latin america. If you pronounce them with different sounds, one an S sound, the other a TH sound, you're a "distinción" speaker, and if you pronounce them both with a TH sound, it's the more uncommon ceceo accent, usually largely Andalusian.
I stand corrected. All of those seem loanwords, but you are absolutely right.
My main point is that if you hear the sounds "th" (za) with e or i 99% it is cena or circo and will not be zena or zirco. It is an heuristic but very reliable.
My favourite word to troll people who are learning the language is "cerrojo" /θe'roxo/, meaning "latch" or "lock", as it contains the three most difficult consonants in the language in sequence xD
I was talking about spelling. I can clearly see how these clusters of consonants characteristic of all Slavic languages can be a pain for a beginner, no matter how you spell them.
No Cyrillic imports, thank you. Russia decided to be the bully and murderer of its closest neighbors, don't need any more russian influence, even if literally just on paper. The further one is from them the more safety and prosperity there is, in every possible way.
What I found helpful in parsing those z combinations is just replacing them with h instead. for example, if you went up to a random monolingual English speaker and showed them "shchotechka" they could probably pronounce it reasonably well. All those z's just throw people off.
