I've often wondered whether the Premier League being the most-watched and lucrative league in the world has anything to do with English being the most widely-spoken language.
Ni Hao!
Mandarin being such a well-used language everywhere outside China.
You would be amazed how much mandarin is only a second language for many people inside China.
Re Dave's original question I think it has to do with 2 main factors, namely the style of play in England and when we play our football. Re style, our football is generally characterised by aggressive, positive play with scant regard to tactics and technique compared to other major leagues. It may produce Chuckle brothers skill levels, but it does make for exciting games.
Secondly, I have watched football in many countries and have found it easy to watch English games in Europe, the Middle East, Africa and Asia because of time difference and kick off times. A 3pm kick off is 10 or 11pm in a large part of Asia, perfect for Saturday night bar watching, as is the 12.45 game. The same games are at 4.45pm and 7pm in the Middle East, again easy for the average punter to watch. Importantly, both continents have shite local football so are attracted by a superior league. Africa follows a similar pattern, based on my travels.
Spanish football has appeal - or at least 2 clubs do- but the later kick offs are not appealing in Asia, though are probably manageable in the Middle East and Africa.
In my experience only in S America do people not give a toss about English football.