I just became a Language Examiner in Canada. We only use 3 levels, 6 Expert, 4 Operational, and "less than 4" non-operational.
If you score 4, you need a retest within 5 years, if you receive "less than 4" you will not be issued a license...
Current License holders have their previous correspondence with TC, and their written tests assessed, and graded upon what is then found. (I by the way, am not a Native English speaker, nor am i French...)
The test is completely oral, and done over the phone, so that there is no physical interaction between the test taker and the examiner.
The test is scenario based and fairly simple, and a pilot at solo level should pass it with ease. Any native english speaker should pass wit flying colors, and if not, usually due to taking the test out of context. It is NOT an aviation exam, it is a language exam.
As it was said before, the easiest way to increase proficiency in a language, is to live there, and DON'T live with people from your country, as you will not speak the new language... (I know, several of my former students have had that problem...)
Cheers
W.