About the language I can tell you that it is spoken by more than 422 million people, who are most of all spread in the arab world. Most of the speakers are muslims, because the Quran their sacred book is only written in arabic. In the middle ages the language was the common one in politics, science and literature and it helped also to spread out new knowledges.
The purpose of this day is to raise awareness among United Nations. Cultural activities in order to celebrate this day include: Music Bands, literary readings, competitive competitions, exhibitions, lectures, artistic performances, play and popularity. It also includes the processing of meals for the cultural diversity of language-speaking countries, the creation of film shows and brief seminars for those who wish to explore more.