No intention of giving you a hard time, bienville just trying to keep things clear. Even apart from the difference between “definition 1” and “definition 2”, I think your question poses yet another difficulty.
The current dominance of English as a language of global communication is something of a unique accident. Firstly, it was spread across the globe by the British Empire; but in this it is no different to several other European languages, and in time its influence would have waned with the withdrawal of Britain from its empire and the various colonies return to self-rule. However, the rise of American economic influence world-wide, and the US’s dominating position in global mass media, has reinforced the position of English as a “first-choice” second language for people all over the world.
I don’t believe that any other language has ever had so wide-spread an influence. Previous languages which filled the role would have been dominant not only in a much smaller area, but also would have varied depending upon the subject to be discussed.
An example: in the Middle Ages in Europe, diplomacy may have been undertaken in French, but matters of science or law would have been dealt with in Latin, while courtly love poetry was freqently in Italian. If a merchant had dealings around the Mediterranean, then Greek might have been the most useful language in the east, but along the south coast he would probably need at least some Arabic.
As you can see, a concise time-line for the whole of world civilisation is probably an impossibility, since all of these elements overlap, not only in geography, but in time.