Most programs use something that is compatible with UTF-8. And UTF-8 is also backwards compatible with ASCII which is why A-z usually works. I actually think UT

Most programs use something that is compatible with UTF-8. And UTF-8 is also backwards compatible with ASCII which is why A-z usually works. I actually think UTF-16 is the most common. The issues start to arise when three or more code points/bytes are combined into one character/glyph.