Unicode is an international standard with the goal to provide the means by which text of all forms and languages can be programmed for use by computers. Your SMS will become a Unicode SMS when you need to use characters outside the GSM 7- bit alphabet. A Unicode SMS can only contain 70 characters. To send more than 70 Unicode characters you can use the preferences Allow Long messages. All the mobile networks don’t support Unicode SMS as for example US destination mobile number does not support Unicode SMS.

Unicode SMS can be used for the following languages:
Afrikaans, Arabic, Croatian, Czech, Danish, Dutch, Esperanto, Finnish, French, Georgian, German, Greek, Hebrew, Hindi, Icelandic, Interlingua, Italian, Japanese, Korean, Lithuanian, Macedonian, Maltese, Persian, Polish, Portuguese, Romanian, Russian, Slovenian, Spanish, Swedish, Thai, Tigrigna, Turkish, Uyghur, Vietnamese and Welsh.