It’s interesting, because people use ‘they’ without thinking for the singular when they don’t know the person and their name might be ambiguous/you just have their surname or a host of other cases.
There are only two gendered singular pronouns in English - He and She. ‘You’ is not gendered. ‘I’ is not gendered. In many Latin languages plurals are gendered ‘ils/Elles’ in French, though ‘we/nous’ is not, interestingly.
Even more complicated is the gender of nouns of course. If you ask a portuguese speaker why ‘table/mesa’ is feminine the only real answer is ‘it just is’. Again, something English doesn’t have, but many other languages do.
Ambiguity is further prevalent in English with ‘you’, as it can be occasionally tricky to know whether the ‘you’ is singular or plural. Also when ‘you’ is used to replace the rather antiquated ‘one’, it can sound quite accusative!
At least English has a non gendered singular (if previously rarely used) in ‘they’. It’s much harder in Latin and some Germanic (don’t get me started on German proper) languages, and I imagine in non Latin languages.
The Finnish language has no gender at all, so they can find this whole debate pretty weird.
I think it would raise a lot more opprobrium if we tried to introduce new pronouns (even more so than it’s already getting), as has happened when people tried ‘Ze’.