Well I¡¯d toss my two cents here

As there are individual differences in second language learning (here specifically English learning for us Chinese), to classify the learning stages is rather strenuous. Thousands of linguists have contributed seas of dimensions to try to figure out language acquisition (My friend Henry is struggling with mountains of such books in Oxford). Yet, all such dimensions have been remaining skeptical. It makes people wonder if we should regard language study as a science. Isn¡¯t language often related to art? Then on, how many learning stages are there in art learning? Yes, we have art schools, but we also have art prodigies.

I do agree to the saying of ¡°functional English¡±, though this term itself is abstract. It can be defined as being able to get by with English on something---to pass an exam, to chat with foreigners or to travel abroad etc. Note here I use the phrase ¡°get by¡±, because you can hardly say your English is good enough in certain aspects. Hence I beg to differ from kwh¡¯s point of view that ¡°one is able to express his or her idea without mistakes¡±. We all still make mistakes even when we already feel very comfortable to command this language. If you are careful, you will find many native speakers make mistakes too. Or take our first language for instance, how many mistakes do we make every day when we speak Chinese? I venture to guess that kwh meant that to such an extent one can express his or her ideas without confusing others.

As kwh aptly point out those two phase may overlap partly for some learners, we might put them as one as well---English learning is once but endless.