What non-slang words give away that someone is not from your country?
As the title says, what are the non-slang, “normal” terms in your language that are a dead giveaway someone is not from your country?
For example, if someone says “tú” I already disregard them as Argentinian. Same with “pues” (in Argentina “pues” is rarely used). These are normal words in the Spanish language that are entirely correct and not slang, but for some reason we don’t use them.
Is there an equivalent for your country?