[Falcao]

I will try to answer the OP questions about Spanish.

Originally Posted by omk3

Want to show off your alphabet?

Spanish has 29 letters. They are the 26 of the English alphabet plus CH, LL, and Ñ.

A, B, C, CH, D, E, F, G, H, I, J, K, L, LL, M, N, Ñ, O, P, Q, R, S, T, U, V, W, X, Y y Z

Before 1994, words starting with CH (LL) would be sorted between words starting with C (L) and D (M). After a reform, those words are sorted like if CH and LL were not separated letters.

For example, the list of the states of Mexico before 1994 was: ..., Campeche, Coahuila, Colima, Chiapas, Chihuahua, Durango, ..., etc. Now the list goes: ..., Campeche, Chiapas, Chihuahua, Coahuila, Colima, Durango, ..., etc.

Originally Posted by omk3

Does your language have a word that has no equivalent in (most) other languages?

Paraphrasing Bruce Willis, I only speak two languages: Spanish and bad Spanish, so I can't really answer this.

One candidate I can think is "tortilla".

Originally Posted by omk3

Does your language have a word, or words, that the whole world is using?

There are some words, like "chocolate", that they were borrowed by the first Spanish colonizers and then spread to the world. However, one can argue that these words are not strictly Spanish words but Aztec words.

I have seen the word "gratis" (free as in "no cost") used a lot in the software world.

I don't know if words like tortilla, tacos, burrito, etc. are known in the world or only in North America.

Originally Posted by omk3

Want to share common blunders learners of your language are making

In Spanish we pronounce all non-mute letters in words and we have full vowels. Thus I have seen that English speakers have problem with that, but maybe that's not a problem for speakers of other languages.

I once met a Chinese guy who told me he couldn't pronounce the "rr" (hard r) sound.

Originally Posted by omk3

Do you have an expression in your language that you find unique, or maybe surprisingly common?

In Mexico we say "el que no tranza no avanza" [lit. those who don't cheat don't advance], and this speaks a lot of our national character.

Originally Posted by omk3

Do you have words that sound the same as in other languages, but mean something completely different?

Yes a lot, they are call false-friends.

One quick example with English is "carpeta/carpet". "Carpeta" means "binder" in English, while "carpet" in Spanish is "alfombra".