There was a group of people called Latins, but for most of the history of the language, people who spoke Latin (even natively) weren’t necessarily Latin people.
And then in the last century or so, “Latin” applied to people is short for “Latin American”. None of whom speak Latin natively.
The term Hindī originally was used to refer to inhabitants of the Indo-Gangetic Plain. It was borrowed from Classical Persian هندی Hindī (Iranian Persian pronunciation: Hendi ), meaning “of or belonging to Hind (India)” (hence, “Indian”).
I was mainly going off what my father told me, Yiddish was his first language. Wikipedia has this explanation " Yiddish (Yiddishיידיש or אידיש(literally Jewish, short for Yiddish-Daitsch or Jewish-German )"
When you get to the section on History, in the topic Terms, it gets really interesting. ‘Yiddish’ might actually be an English word meaning ‘Jewish’, eventually adopted by German. And more stuff I didn’t know until now too.
So it does refer to the people and the language in English, but maybe only Yiddish speakers and not all Jews if someone at the time made such a distinction.
Although it wasn’t very many years ago that the country was also called Persia.
Country names (and borders) change a lot more quickly than ethnic groups move around regions or than languages colonize new areas. Or than groups or languages get new names.
True Tagalog is the most widely spoken language in the Republic of the Philippines, but the standardized version mostly based on Tagalog is called Filipino.
Then there’s parts of the world where ethnic groups and nationalities aren’t the same. People from Bosnia are Bosnians, but the ethnic group who tend to be Muslim associated with the country are Bosniaks. But you can be a Bosnian Serb or Bosnian Croat.
Do slight differences in word forms also count? The ethnic group that speaks the language Arabic is called Arabs.
Hebrew is another example. In past centuries it was often used synonymously with Jewish to refer to the people, but that has fallen out of use. So the people are Jewish, or they’re Israeli if they are nationals of the Middle Eastern country that has Hebrew as an official language, but the language is Hebrew. (And of course additional complications set in since there are Jewish people who are not Israeli by citizenship, and who don’t speak Hebrew, and conversely there are people who speak Hebrew and might be Israeli but are not Jewish…you get what I mean).
That’s also a complicated case, since “Esperantist” can refer either to a person who simply speaks Esperanto, or to a person who studies Esperanto systematically and supports the Esperanto movement. It’s difficult to distinguish the two since there are almost no native speakers in the language, so anybody who speaks the language is likely to do so out of an interest in and support for the movement. But the confusion has been noted within the Esperanto community itself, which is why it is sometimes preferred to use “Esperanto speakers” (Esperanto-parolantoj) if you just want to say that someone speaks the language, with no further ideological connotations.