Is there a common language in the world?

Is there a common language in the world? 

Is there a common language, lingua franca, in the world? No. If it is a spoken language, hearing impaired people cannot use it. If it is a written language, visually impaired people cannot read it. So it is impossible that there is a common language in the world. 

If taking hearing and visually impaired people aside, is there a common language in the world? Yes, it is. After age of discovery, people in the world need a common language to communicate. 

The basic building blocks of a common language is convenient communication and easily accessible. Now English is practically common language, especially on the internet. However it is not the only one language in the world. The reason is that the world is so large, and the population is so big. In addition, language are changing all time.  

Chinese translation

世界上有通用语言吗？ 

世界上有通用语言吗？没有。因为如果这种语言是口语，聋哑人肯定听不见。如果这种语言是书面语，也就是文字，盲人肯定看不见。所以世界上不可能有通用语言。 

如果不考虑聋哑人和盲人，世界上有没有通用语言？肯定有。大航海以后，全世界人民需要一种通用语言来交流。交流和接触是通用语言的基石。 

现在英语就是实际上的通用语言，尤其是在因特网上。然而世界上不可能只有一种语言，因为世界这么大，人口这么多。还有语言是不断变化的。