> do you need to know anything about Roman culture to understand Latin grammar? No.

But you do need to be fluent in Roman culture to understand Latin jokes, puns, similes, metaphors, and all the other things that go into meaning.

For a more modern example: Observe how British English can turn almost any noun into an insult in much the same way that this just doesn't work in American. Or how a Californian can say "this is not my favorite" and we all know they mean "this is awful". Or how Australians can use "you c*nts" as a term of endearment, but Americans cannot. Meanwhile Americans can use motherf*cker as both a term of endearment and an insult depending on situation.

And who could forget the subtle difference between "You are shit" and "You are the shit". Where does that show up in grammar?

edit: oh here’s a good one! The phrase “I love you” changes meaning when you say it to family, friends, coworkers, strangers, performers on stage, etc. Some languages even use different words for those meanings, but they all translate to “love” In English.

You absolutely cannot understand the full meaning of language without understanding the speaker’s context.

> But you do need to be fluent in Roman culture to understand Latin jokes, puns, similes, metaphors, and all the other things that go into meaning.

You need to understand Roman culture to understand Roman jokes, but that is a property of Roman culture, not the Latin language. You could translate American jokes into Latin, and then a hypothetical American who can speak Latin but doesn't know anything about Roman culture would be able to understand and find them funny.

Of course, you can't understand the full meaning of an utterance that someone utters in a particular context without understanding who that person is and what the context is. A Roman who somehow spoke perfectly grammatical English would still probably be hard for us to understand. But that's a property of an utterance, not the language itself.

I completely understand what you're saying, but I think the problem you run into when trying to make too hard a dividing line is that it's very hard to describe precisely where "language" stops and where "culture" begins.

For example, in the sentence "I think you should do that", with an emphasis on the "you", what is the grammatical role of that emphasis? It's not necessarily something you'll find explicitly in an English textbook, but it is conveying important meaning here. It's also cultural - I will use different forms of emphasis of I'm from the US or from the UK. In the US I might speak louder for emphasis, in the UK I might speak more slowly for emphasis, or use a different word choice.

But what happens if I'm culturally British, in the UK, a native English speaker, but speaking a sign language like BSL? Well then I'm going to use a different form of emphasis again, because BSL has its own ways of indicating emphasis. So clearly emphasis is also related to the language one speaks - my culture hasn't changed, after all!

This is the issue with splitting language to into a cultural part and a linguistic part - too much of language straddles both sides. You might say that the core of a language is its grammar, but Scots English and AAVE are both grammatically different from Standard British English, and yet the differences there are as much cultural as purely linguistic.

In principle, I get what you mean - you can learn all the words and the grammar of a language from a textbook without knowing anything about the culture behind that language. But if you can't use the language to communicate fluently with native speakers of that language, have you really learned it? Your time traveling Roman asking for the portal rather than the door has basically just invented his own dialect, not learned English to any meaningful degree.

> Your time traveling Roman asking for the portal rather than the door has basically just invented his own dialect, not learned English to any meaningful degree.

A fun argument for how important this is: The only reason we have Middle Earth, Lord of The Rings, etc is because Tolkien needed a world and a history to embed his languages in. Otherwise they couldn’t have any real meaning. He could construct the grammar, yes, but not the semantics.

Even something as simple as what our shortest words encode tells a lot about our culture or history. We use short words for things we say often.