It really seems like in close future all population will communicate on one international language, such as English or Chinese. In my view it will have only positive impact.
Firstly, maintaining my suggestion, having one chosen language all over the World, will destroy language border between different cultures and make communication much more easier. For instance, being not necessary to study new language, will greate impact on travel cross countries in reason of having no troubles in conversation with local community. Universities' regards in language certificate will also disappear, therefore the number of students educating abroad will extremely increase. A lot of materials like books for studying, entertainment and many other purposes will be available on the Internet, shops and stores.
Secondly, single language will bring clother together different cultures and increase unity among all countries. Therefore, the number of conflicts and wars between goverments can decrease and world will be one step closer to the peace, what is really great achievement for all humanity.
In conclusion, single international language will make people life much more easy and will create a number of opportunities both for old and young generation. That is why in my vision it is great step forward.