How can you not conflate language and culture? The two are inseparably intertwined. While not all people who speak the same language (or more likely, dialects of it, e.g. American vs British vs Indian English) will have extremely similar cultures, I don't think there's any good examples of people speaking very different languages and having extremely similar cultures. Language and culture go hand-in-hand. Even for the different dialects, the cultures between UK, USA, and AUS/NZ are still very similar to one another; India is rather different but the way they adopted English is also very different and still for them it's really a 2nd language and used within India as a convenient common language because they refuse to standardize on Hindi as some wish. There is far, far, far more similarity between Australian culture and American culture, for instance, than Mexican culture and American culture.
You assert that there's more similarity between American and Australian culture than American and Mexican. I don't believe that. US cuisine borrows more heavily from Mexico than Australia. We have more Spanish speakers than Spain. We have Veep candidates pandering to them. The US and Mexico both like fake wrestling. We have large cities with Spanish names and an entire state named after Mexico.
But it's a dumb argument to go into because I probably won't convince you about cultural similarity and vice versa.
On the other hand, language can be quantitatively measured and gives an opportunity to ambitious people around the world.
>US cuisine borrows more heavily from Mexico than Australia.
This is just dumb. US cuisine borrows more heavily from China than from Australia too, but no one is going to claim that US culture is very similar to Chinese culture. I live in a little town and there's 3 Chinese restaurants here, and only 1 Mexican.
>We have more Spanish speakers than Spain
We probably have more Chinese speakers than Hong Kong too, but that doesn't make US culture similar to China either. The US is a huge country, #3 in the world by population. Of course it's going to have a lot of foreign-language speakers, especially when there's a ton of Spanish-speaking countries to the south and a lot of immigration from there. But that doesn't mean that the dominant culture in America today is extremely similar to the culture of Mexico; I'd argue that German culture is more similar to American culture. At least German culture is universalist, rather than particularist as are Latin American cultures.
