>Understanding this word takes not a fluency in the language but rather a fluency in Mexican culture.

Wrong. I am native in spanish, not even near to "fluent" in "Mexican culture" and I can understand it. I think any Spanish speaker older than 5 can understand it.

Latin America has a myriad of different accents and dialects, far more than in the United States (think more of a UK kind of thing). Some say "ahorita", some don't; but everyone can understand it.

All in all, the article is pretty inaccurate.