The Words
Everyday casual words — the kind you hear on the street, in the taquería, in the office WhatsApp thread.
Slang
About Slang
Single informal words, and the biggest category here by some distance. Chido, güey, chafa, lana, chamba — the vocabulary that makes up ordinary casual speech and almost none of which appears in a course book.
Slang is also the most register-sensitive part of the language, which is why every page carries a tone note. Plenty of these words are completely neutral among friends and land badly at work, and there's nothing in the word itself to warn you. That's the bit worth reading before you try one out.
Register is the whole game
Almost every word here is neutral somewhere and wrong somewhere else, and nothing in the word itself tells you which. Güey is affectionate between friends and hostile from a stranger. Chido is fine nearly everywhere and still faintly juvenile in a boardroom. The vocabulary is the easy part; reading the room is the skill.
The second trap is age and geography. A lot of Mexican slang is generational, and words that were current in the nineties now sound like a parent having a go. Others are firmly regional — chilango vocabulary does not automatically travel to Monterrey or Mérida, and using a CDMX word confidently in the wrong state marks you about as clearly as using none at all.
Which is why every page here carries a tone note rather than just a translation. The learner failure mode is almost never picking the wrong meaning; dictionaries handle that. It is picking an entirely correct word and using it at a table where it does not belong, and noticing the room go slightly quiet.
Slang — common questions
Is güey rude?
Between friends, no — it works roughly like "dude" and often carries real affection. From a stranger, or in a formal workplace, it can read as aggressive or dismissive. Same word; the relationship decides.
Does Mexico City slang work everywhere in Mexico?
Not reliably. CDMX vocabulary dominates national media so it is widely understood, but plenty of it sounds distinctly chilango elsewhere. Monterrey, Guadalajara and the Yucatán each have their own sets, and locals notice.
How much slang should a learner actually use?
Less than you can recognise. Understanding a hundred words pays off immediately; using ten of them well beats using forty approximately. Slang deployed at the wrong temperature is far more noticeable than no slang at all.
Is chido outdated?
No, though it skews casual and slightly younger. It is in ordinary use across Mexico. Padre does similar work and sounds marginally more neutral if you want the safer option.