There´s an interesting effect based on the size of the country...
Small countries "look outside" a lot more than larger countries...which is logical really since there´s not a lot going on at home.
Check this out: People from New Zealand are very aware of language differences and know most Britishisms and most Americanisms, for example. People from England are relatively aware of Americaisms too. But, try testing the average American with some Britishims - he´ll be hard pressed to tell you what they mean.
This feature is of course not limited to language awareness. It´s simply a mathematical function, and there´s not much that can be done about it.