[latte]

By who's authority should the word "who's" be spelled "whose" and not "who's"?

In all seriousness, it's interesting to see how the live language is diverging from the rules. The dual ending "-ayim" is supposed to be used with the singular stem: nekuda(-t) - giving nekudatayim "two dots", and likewise shnatayim "two years", dakatayim "two minutes", etc. But in practice, speakers classify dual as plural and use the form with both plural and dual endings: nekudotayim, dakotayim

[Adverblessly]

To be fair, Hebrew does have an official regulatory institute in the (ironically named) Academy of the Hebrew language. But indeed 100% of modern Hebrew speakers will say "nekudotayim" and not "nekudatayim" and maybe eventually the academy will catch up with that and make it official (just like they somewhat recently did with socks :)).