[neaden]

You're not a purist, you're just incorrect. We are speaking English, so saying that it is redundant isn't true. Just like how Hound means generic dog in German but hunting dog in English, or rouge means red in French but means a kind of makeup in English, Chai doesn't mean tea in English and thus there is no redundancy here.

[ra7]

Chai means (Indian) tea with milk. It’s a borrowed term in English that already includes the meaning. Just like you don’t use “yoga exercise” in English because yoga already means a form of exercise. Or the usage of “karma” in English. You don’t say “karma fate”.

You might want to revisit who’s incorrect.

[neaden]

Yes, loanwords don't operate consistently when brought from one language to another. That does not mean that one way they work is "wrong" and the other way is "right", it just means language is complicated. You're the one coming here and telling people they are wrong.

Edit: Like in Italian Latte just means milk, but in English it means an espresso with steamed and then frothed milk on top, what would be called a cappuccino in Italy usually. Americans calling it a latte aren't wrong, they're just using a loanword to mean something different then the original language.

[ra7]

How is chai tea used differently in America then? If I ask for it in a coffee shop, I usually get chai (tea) with steamed milk, which is exactly what the original usage is.

[neaden]

Looking at the Starbucks app right now for example on their menu: Chai tea is black tea with clove, cardamom, cinamon, and ginger and no milk by default, Chai Tea Latte is that black tea and spices with steamed milk. You'll also see Chai sometimes to refer to the spice mix sold without any tea.

[ra7]

In my local coffee shop, I get black tea with steamed milk (called chai tea).

They also sell masala chai, which is the above + spices added.

Starbucks uses chai tea and chai tea latte to mean something else.

Some grocery stores (Trader Joe's?) sell chai as just a spice mix.

So Americans aren't really using it "differently" as much as they're using it wildly inconsistently. That's not really the same as cappuccino vs latte, is it? Latte is at least used to mean the same thing across the country.