I strongly doubt that their methodology has any validity at all for non-native speakers. Extrapolating from a selection of 60-80 words presupposes a relatively normal developmental history; otherwise one would not be able to draw the primary inference at work here, namely that somebody who knows a definition for "mawkish" knows definitions for all words of similar difficulty and frequency.
Atypical language acquisition (e.g., as a second language, or through a non-standard channel like technology or fantasy literature) disrupts this extrapolation step. For instance, a German programmer that knows the word "polymorphic" via OOP is less likely to know similarly frequent and difficult but programming-unrelated words than British or American peers. So adding, say, 100 to the total would be utterly unfounded. Same thing for a science-fiction nerd: Acquaintance with obscure words from one domain doesn't extrapolate to other domains.
Unless they somehow control for domain specificity and atypical acquisition, let's not get too frustrated. (Disclaimer: Not a native speaker -- result around median.)
Hi, creator of the site here -- I worked for several years teaching English to foreigners, and my own (informal) statistical research has found that native and non-native language acquisition, while certainly somewhat different, is not tremendously different. I've run this test on Americans and Brazilians at all different levels, and the size of the progression from known to unknown words is rather consistent.
That being said, cognates between languages can give an artificially inflated score. I intentionally avoided any words with the same roots in English and Portuguese (my second language), which should hopefully also be true for most Romance languages. This way, you shouldn't be able to "guess" meanings you've never actually learned. However, it wouldn't surprise me if German speakers, for example, were able to "guess" an additional number of words correctly.
Also, the 60-80 words are only what you are tested on -- the word selection on pages 2-4 changes depending on your answers on the first page, so it attempts to narrow down your vocab knowledge "at the margin".
Non-Native speaker here. I found out that in almost all cases i knew a synonym of the words is didn't know. The problem is these are the ones that are used very frequently so i am rarely exposed to the other forms. While i know high literature in German, i must admit i just have read non-fiction in English so far. This is really a shame and i am going to change this.
This test made me aware of that fact, regardless of it's scientific accuracy.
I back you up.
Non-native english speaker here. My result: I know 10,600 words. I really doubt it, I have an english dictionary that contains about 4,000 words and I don't think I need another dictionary. Plus my computing terminologies, 10K words is still way beyond me
I'm not sure it's valid for native speakers, either.
Your basic vocabulary will be the same as most other speakers because we have structured learning in our schools.
But the less-well-known words are generally learned in context... So if you haven't happened across them in a book, you probably don't know them... But there are probably many others that you do, instead. This test could easily hit a bunch you don't know and totally miss all the ones you do.
Atypical language acquisition (e.g., as a second language, or through a non-standard channel like technology or fantasy literature) disrupts this extrapolation step. For instance, a German programmer that knows the word "polymorphic" via OOP is less likely to know similarly frequent and difficult but programming-unrelated words than British or American peers. So adding, say, 100 to the total would be utterly unfounded. Same thing for a science-fiction nerd: Acquaintance with obscure words from one domain doesn't extrapolate to other domains.
Unless they somehow control for domain specificity and atypical acquisition, let's not get too frustrated. (Disclaimer: Not a native speaker -- result around median.)