Cantonese keyboard predictions: The new Cantonese predictions for Traditional Chinese Cangjie, Sucheng, Stroke, and Handwriting keyboards bring more relevant character and emoji predictions to Cantonese users.
Improved Japanese predictions: A new neural language model takes words typed earlier in the sentence into account, so predictions are more grammatically consistent and relevant to the subject matter.
New fonts for Indian languages: Get 34 new fonts, including four system fonts and 30 document fonts, for languages like Gujarati, Hindi, Kannada, Odia, Punjabi, and many more.
New Indian English Siri voices: All-new Indian English male and female Siri voices allow Siri to be more natural and expressive.
New dictionaries: New dictionaries include Thai-English and Vietnamese-English.
Because Mac and Windows keyboard layouts for many languages are slightly different, it can be confusing to use an Apple hardware keyboard with Windows which has been installed on a Mac. The usual fix is to find, inside the WIndows install, a layout which has (Apple) after the normal name. Where that does not exist, you have to download and install a custom layout in the Windows system. A source for these is
Users who have to switch from the standard US ANSI keyboard to the European ISO version, which has an additional key between Shift and Z, are sometimes annoyed because the Tilde character moves from under ESC to that extra key. Here is a custom keyboard layout which puts Tilde back under ESC.
The poster mitjam in the Apple Support Communities has created two custom Slovenian keyboard layouts which readers who use that language may find useful.
Slovenian - @, which is equal to original mac Slovenian one, except there are exchanged key combinations for characters @ and ™. You get '@' with keys ⌥ + 2.
Slovenian - PC, which is a mac Slovenian keyboard layout, useful for Slovenian PC keyboard. The basis is original mac Slovenian layout, whereas there are visible engraved characters from PC keyboard (that are different from Slovenian Mac layout) appropriately attached to particular key combinations. And keyboard is QWERTZ instead of QWERTY, to correspond to PC layout.
While MacOS has had apps enabling ordinary users to easily make custom keyboard layouts (e.g. Ukelele) for a long time already, the same is not true for iOS. Users still have to rely on apps produced by developers and offered via the app store. Below is some info on how these can be made by people with the necessary skills. The first link relates to making files for the Keyman app, which have to then be compiled on a Windows machine. The other 3 are tutorials for iOS programmers.
These links are only for screen keyboards. Development of hardware keyboard layouts remains a mystery.
In a recent discussion in the Apple Support Community (ASC) a user complained that a certain Chinese character was not being displayed correctly. As it turned out, it was one of those where the Chinese and Japanese forms are quite different, and his phone was displaying the Japanese version. This is caused by the device using a Japanese font, instead of a Chinese one, whioh will happen if Japanese is higher than Chinese in the Preferred Languages list. The particular character was the one for "drink":
For other examples of characters where this can occur, see the chart labeled "Same code point, different language tags" on this page.