That's not that uncommon, Scottish Gaelic and Irish, both spoken in the UK (take note British Broadcasting Corporation), have that same quirk—at least traditionally. There's some anecdotal evidence that with the number of non-native speakers learning the language, that Tá/Níl and Sea/Ní hea are starting to fill that gap in Irish.
> including lacking any standard way of negating a sentence, [...], or any words for direction.
These are much more interesting features (or lack thereof)! Why wouldn't the article lead with that?
EDIT: This is even funnier after seeing that the author even has a name of Scottish Gaelic/Irish origin: Eileen McDougall.
"sic" -> si/sim (italian, spanish, portuguese)
"hoc" -> oc (occitan)
"hoc ille" -> oui (french)
A few examples:
* Daniel Everett made an entire career out of claiming various dubious things about the Piraha language, including that it has no colors other than light/dark, lacks recursion and has phonemes used in no other language on the planet https://en.wikipedia.org/wiki/Pirah%C3%A3_language#Unusual_f...
* Guugu Yimithirr supposedly only has absolute directions (north, west, etc, instead of left, right) https://en.wikipedia.org/wiki/Guugu_Yimithirr_language
Languages without yes and no are called echo languages. English used to be four-form with yes/no and yeah/nay, but now it's two-form.
Nothing strange about this. I think Chinese is similar too. The intention of the speaker is more important than the words he/she says.
Related (and one of my fav papers in linguistics) - Interality as a Key to Deciphering Guiguzi: A Challenge to Critics https://cjc-online.ca/index.php/journal/article/view/3187
Rather, Chinese responds indicates affirmative or negative by repeating the verb of the question in either plain or negated form.
e.g.
Q: Do you like hot pot? A: like | not like Q: ni xihuan huoguo ma? A: xihuan | bu xihuan
Q: Do you have covid? A: have | not have Q: ni you mei you wuhan feiyan? A: you | meiyou
Q: Are you american? A: is | is not Q: ni shi meiguoren ma? A: shi | bu shi
etc.
This was quite strange to get used to, but makes perfect sense once internalized.
E.g. Q: Aren't you finished yet?
Answering 'yes' or 'no' would be ambiguous
"What you said is true."
"I agree with what you said."
"What you said is false."
"I will do what you said."
"I will not do what you said."
"I did that."
"I didn't do that."
"The ball is blue."
"The ball isn't blue."
好 = OK,
是 = Is,
Both are used to mean yes
不要 = Don't want,
不用 = Don't need,
Both are used to mean no
I wonder how you can be a fluent speaker if you have nobody to talk to?
see what I did there?
> Their language, also called Kusunda, is unique: it is believed by linguists to be unrelated to any other language in the world. Scholars still aren't sure how it originated.
Languages with no known relatives are called isolates, and there are a lot of those: https://en.wikipedia.org/wiki/Language_isolate And languages do not normally "originate", unless they are constructed, like Esperanto, or arise in unusual circumstances, like spontaneous sign languages in isolated deaf communities.
> And it has a variety of unusual elements, including lacking any standard way of negating a sentence, words for "yes" or "no", or any words for direction.
As pointed out in other comments, not having words for "yes" or "no" is not very surprising. As for a "standard way" of negating a sentence, I wonder what that means. Kusunda has negative verbal suffixes, which vary based on some grammatical features, but so do many other languages. Location and direction is also usually specified by suffixes like in, e.g., Hungarian or Finnish.
See a grammatical overview for details: https://escholarship.org/uc/item/83v8d1wv