Hah, from the article: "Scientific linguists have long understood that ability to speak a language fluently does not necessarily confer a linguistic knowledge o

Hah, from the article: "Scientific linguists have long understood that ability to speak a language fluently does not necessarily confer a linguistic knowledge of it, i.e., understanding of its background phenomena and its systematic processes and structure, any more than ability to play a good game of billiards confers or requires any knowledge of the laws of mechanics that operate upon the billiard table."