Vocabulary size

A few questions that occur to me after attending a CELTA course.

I hear that a vocabulary of about 3000 words (base forms I assume) is
adequate for communication in English. Can someone qualify this more
closely - e.g. what degree of proficiency would such a speaker have
reading books/papers.

Is a list of such high frequency words available somewhere?  

Does the same go for languages such as Spanish (again, if so, where is
such a list)?


On a separate note, I hear that Swedish speakers of English, though
often as proficient as native English speakers have little knowledge
of grammar (again like native speakers).  What method do they use to
teach English in Sweden?

Thanks for any replies
William