'Your total vocabulary size is estimated to be: 39,200 words.'
Not bad—I thought I'd have scored less. It certainly helps to know Latin and Greek, as well as another modern European language, especially French (which I do, plus a smattering of Italian). But even then, English writers have long obsessed over verbal precision, and knowing these languages does not always clarify, or even point to, the meaning of all the English words we have borrowed from them. Our wordstock is so huge and diverse, especially considering all the jargon, that there is nothing of it but to have a dictionary close to hand to learn the meaning, and likely the pronunciation, too. Many other languages are more content to assign a specific technical sense to a word that has long been familiar, whereas English often prefers to borrow a foreign word or construct one from Classical roots. Though I especially love Old English/Anglo-Saxon for aesthetic reasons, I really wish sometimes that English had evolved more like German (or even more extreme, like Icelandic), with a retention of much of the native vocabulary, and a reliance on native roots to construct longer, more complicated words (or multiple words). Spelling would be much easier, grammar would probably be more consistent, and it would be easier to learn more complicated words since they'd derive from native shorter words and affixes. Of course, there would be no Chaucer, Shakespeare, Milton or any of the other greats as we know them, but I'd still prefer it.
A word of comfort and encouragement, too, to those dissatisfied with the size of their vocabularies: a large vocabulary is no guarantee of being a skilful writer, though it certainly can help. On good writing, H.W. Fowler remarks in Modern English Usage in 'Love of the Long Word' that, 'It is a general truth that the short words are not only handier to use, but more powerful in effect; extra syllables reduce, not increase, vigour. This is particularly so in English where the native words are short and the long words are foreign,' and, 'Good English does consist in the main of short words.' Now, I'm guilty, as many others are, of waxing pedantic, but as the years have passed, I've come to appreciate simpler writing. Much of that opinion was my experience in the academic world. Simple language allows a writer to connect a genuine level with a reader and establish trust. Loading diction with polysyllabic monstrosities and foreign vogues creates what feels like veil after veil of disconnexion. At extremes, it's an author's descent into solipsism. A doubting writer can easily hide behind such diction when others offer criticism.
So, sure, learn those weird words if you like (I enjoy it, just because they're exotic), but trust in the everyday. It will serve you well.