I think you're making a very good point here – understanding "unless" (quickly, i.e. without having to think about it) very much depends on one's understanding of the English language and/or one's mother tongue. Sure, one can probably get used to it (like one gets used to what "if/else" means etc.), but it definitely increases the mental effort needed to read & understand code.
I think we're going to have problems if we try to make all languages consistent for users of all languages.
If and unless are English language keywords besides being Ruby keywords; and in Spanish, the word for "if" and the word for "yes" only differ by an accent mark.
Same in Spanish!
I think you're making a very good point here – understanding "unless" (quickly, i.e. without having to think about it) very much depends on one's understanding of the English language and/or one's mother tongue. Sure, one can probably get used to it (like one gets used to what "if/else" means etc.), but it definitely increases the mental effort needed to read & understand code.