Điền từ thích hợp vào chỗ chấm

Language is a (1) ___________ of communication so each nation has its (2) _______________ language. However some nations have the same language. According to the speakers' use of language, it is called the first, second or (3)_______________ language. Among the languages used by most people in the world (4) _________________ English. This does not mean that English is spoken by greater number of speakers (5)________________ any other languages, for it is easily (6) _______________ by Chinese in this respect. However, it is (7)________________ most international of languages because it provides ready access to the world scholarship and world trade. That is the (8) __________________ why millions of men (9)______________ women try (10)_______________ master it.