Levels at Duolingo and the Common European Framework of Reference for Languages
Can anyone tell me what level has someone who finishes the 25 levels of the tree on the scale from A1 to B2 ?
This scale or framework is a widely used reference to assess language knowledge.
Just to clarify: the levels (1-25) are based on the number of points a user has rather than where they are in the tree. You can (theoretically) get to level 25 just by repeating the first lesson over and over again. Levels don't necessarily correspond with skill or knowledge.
The tree will get you somewhere between A2 and B2, on different aspects. Duolingo is pretty good about teaching grammar, and gives you a large enough vocabulary to communicate, but not at a very high level. It also doesn't give you speaking practice or much listening practice. The result is that upon finishing the tree, you'll have skills all over the place, maybe with B2 grammar, B1 vocab and reading comprehension, and A2 or even A1 speaking.
Duolingo's a great resource, but it doesn't do everything.
For university I have been working with quite a few frequency dictionaries (in Spanish, French and Swedish) and usually B2 level vocabulary would require one to know about 7.000 individual lexemes (not including inflected word forms). Since most courses here take you to around 1500-2500 lexemes, I suggest the level to be closer to an A2 level, which also correlates with the fundamental grammar structures being tought. But of course, this varies slightly from language to language.
7000 must be a typo. The highest levels in these types of assessment systems generally end at 5000. I don't know how high the European system goes, but even if B2 is the highest, it would be somewhere around 5000.