> Not sure what CJKV users do.

Chinese: the physical layout is always ANSI US. Depending on the IME you might want more than roman characters printed on keycaps, but it's just cosmetic if you can touch-type.

Japanese: most keyboards use the JIS layout and visually support multiple IME, but if you stick to romaji, using an ANSI US keyboard works too.

Korean: the physical layout is ANSI US (sometimes with 2 extra modifiers). Hangul is a proper alphabet, symbols are made up of subcomponents (jamo) that are printed on the keys. Again it's just cosmetic.

In my experience, people of my generation (30-40 years old) who are educated know to touch-type. For instance I've never met a Taiwanese that needed to look at the Zhuyin symbols on a keyboard.

But I've heard that's not the case anymore with kids that grew up using smartphones.

Just to expand on this, at least in Mandarin, one types out phonetic Latin alphabet-based pinyin and the system prompts you with choices of matching symbols in the same way that predictive keyboards show you words. You select which characters to insert by clicking/tapping on them or hitting a number key. The only big difference is that the same pinyin might correspond to any number of characters and you might have to search through a lot, but context and frequency helps it suggest the right ones to you. (Mandarin only has 409 different pinyin 'syllables' when ignoring tones, which aren't typed in this system. Even with tones, there's only like 1200. These map to many thousands of characters, obviously not one-to-one. Depending on how you count, English has something like 16000 syllables.)

Works pretty the same in Japanese, they just have their own syllabic scripts (two of them), but the entry method can support them as well.

Based on the pinyin based Chinese input method I've seen, I guess the user will want to switch to US for entering code, right? Otherwise, the IME will offer Chinese characters...

What I like about using US Intl (I've modified it slightly) is that no switching is required, I can conveniently enter both the programming related characters (such as curly braces which require gymnastics with a German keyboard layout) and the German specific characters such as umlauts.

But I can't imagine that this could be possible for Chinese without switching modes (or input methods or keyboar layouts).