Using UTF-8 characters

ASCII characters other than A-Za-z0-9:

!"#$%&'()*+,-./:;<=>?@[\]^_`{|}~

Non-ASCII characters that sort-of work:

€•™¢©®

Here is "Hello!" in:

German - Hallo!
Albanian - Përshëndetje!
Scots Gaelic - Halò!
Korean - 여보세요!
Russian - Здравствуйте!
Greek - Γειά σου!
Hindi - नमस्कार
Punjabi - ਸਤ ਸ੍ਰੀ ਅਕਾਲ
Chinese - 你好