TPTQ Arabic fonts support 85 languages, however not every version of every font supports every language. For example if you use both English and Czech in a document, you need to use a version of the font which supports those two languages. PostScript fonts offer limited language support and you would have to use two different PostScript fonts, one with Western and one with Central European encodings. The OpenType format simplifies matters, as a single font can support several encodings, (for example, Latin, Central European, Vietnamese, Cyrillic and Greek).