How did English - the language of such a small island - achieve its present-day international status?

It's all about colonies and buisiness. You know, in the 17th century, which the Dutch call the 'golden age', Holland had so many colonies and so much economical influence around the globe that Dutch was an international language, just like english is today. Imagine that, since Holland (now the Netherlands) is even smaller than england/the UK.

I suppose the industrial revolution may have given the UK the economic influence to turn english into an international language, and since then the UK has become less influential, but no other country has really taken it's place, sothat the international language did not change.

in large parts of africa, french is much more important, since those area's were colonized by the French.

In simple terms, through war and business.

'cos we took over most of the world in the past. The language (like the people) is a mixture of Norse, Latin, Germanic, Celtic and a few others.

It wasn't done in a day.It took years of chronological events to give it it's present status.First were the explorers,the traders,then came the colonialism.Colonialism did spread from south america till extreme east asian countries.During industrial revoluttion and in the after years,the Brits needed officials to do lower jobs and their(our) loyalty didn't permit them to recruit people from England.So,they educated the locals with the english language to do low profile jobs and that's how they spreaded it all over the world and whatever regions were untouched by colonialism,the christian missionaries played their part in it.

The power of the Royal Navy and the arrogance of a small island nation that thought it could take over the world - and then went on to prove that they could.