*Different resources give slightly different answers, but in general, these are the results:
Intermediate: 3,000 words
Advanced: 6,000- 8,000 words
Highly educated native fluency: 25,000 words
1000 words allow you to understand about 80% of the language which surrounds you, as long as it is not too specialized.
In theory, it sounds great. JUST 1000 words and you understand that much! Unfortunately, the remaining 20% is what really matters.
Just look at this sentence:
âI went to the ⊠to buy âŠ. but they told me that they canât ⊠.â
Sure, you understand a lot of words. But does it really help?
3000 words allow you to understand about 95% of most ordinary texts (Hazenberg and Hulstijn, 1996).
It seems like a lot. Sure, on this level, you will be able to hold a decent conversation. You will also be able to get the general ideas and concepts of most of the articles.
BUTâŠgeneral comprehension is not the same as full comprehension, as it involves some guessing.
Still, there is no shortage of enthusiasts who claim that such level is high enough to start picking up new words from context. However, researchers tend to disagree and say that the âmagicalâ number of words which allows learning from the context isâŠ.(drum roll)
5000 words allow you to understand about 98% of most ordinary texts (Nation (1990) and Laufer (1997)).  Such a vocabulary size warrants also accurate contextual guessing  (Coady et al., 1993; Hirsh & Nation, 1992; Laufer, 1997).
It means that you can function surrounded by this language without bigger problems. Sure, you will struggle if you want to formulate your thoughts really precisely, or when you encounter specialized vocabulary.
But other than that, you will be fine.
10,000Â words allow you to understand about 99% of most texts (Nation (1990) and Laufer (1997)).
This is the pinnacle of language learning. A counterpart of having the vocabulary of a college graduate.
With that many words, you can express yourself with amazing precision and pass for a native speaker if your accent is good enough.
Wondering what are the most common words to start learning? Here's some help:
(total is about 600 words. add in some grammar and you're off to a great start!)
EXPRESSIONS OF POLITENESS (about 50 expressions)
âYesâ and 'noâ: yes, no, absolutely, no way, exactly.
Question words: when? where? how? how much? how many? why? what? who? which? whose?
Apologizing: excuse me, sorry to interrupt, well now, Iâm afraid so, Iâm afraid not.
Meeting and parting: good morning, good afternoon, good evening, hello, goodbye, cheers, see you later, pleased to meet you, nice to have met.
Interjections: please, thank you, donât mention it, sorry, itâll be done, I agree, congratulations, thank heavens, nonsense.
Time: morning, afternoon, evening, night; Sunday, Monday, Tuesday, Wednesday, Thursday, Friday, Saturday; spring, summer, autumn, winter; time, occasion, minute, half-hour, hour, day, week, month, year.
People: family, relative, mother, father, son, daughter, sister, brother, husband, wife; colleague, friend, boyfriend, girlfriend; people, person, human being, man, woman, lady, gentleman, boy, girl, child.
Objects: address, bag, book, car, clothes, key, letter (=to post), light (=lamp), money, name, newspaper, pen, pencil, picture, suitcase, thing, ticket.
Places: place, world, country, town, street, road, school, shop, house, apartment, room, ground; Britain, name of the foreign country, British town-names, foreign town-names.
Abstract: accident, beginning, change, color, damage, fun, half, help, joke, journey, language, English, name of the foreign language, letter (of alphabet), life, love, mistake, news, page, pain, part, question, reason, sort, surprise, way (=method), weather, work.
Other: hand, foot, head, eye, mouth, voice; the left, the right; the top, the bottom, the side; air, water, sun, bread, food, paper, noise.
PREPOSITIONS (about 40 words)
General: of, to, at, for, from, in, on.
Logical: about, according-to, except, like, against, with, without, by, despite, instead of.
Space: into, out of, outside, towards, away from, behind, in front of, beside, next to, between, above, on top of, below, under, underneath, near to, a long way from, through.
Time: after, ago, before, during, since, until.
DETERMINERS (about 80 words)
Articles and numbers: a, the; nos. 0â20; nos. 30â100; nos. 200â1000; last, next, 1stâ12th.
Demonstrative: this, that.
Possessive: my, your, his, her, its, our, their.
Quantifiers: all, some, no, any, many, much, more, less, a few, several, whole, a little, a lot of.
Comparators: both, neither, each, every, other, another, same, different, such.
ADJECTIVES (about 80 words)
Color: black, blue, green, red, white, yellow.
Evaluative: bad, good, terrible; important, urgent, necessary; possible, impossible; right, wrong, true.
General: big, little, small, heavy; high, low; hot, cold, warm; easy, difficult; cheap, expensive; clean, dirty; beautiful, funny (=comical), funny (=odd), usual, common (=shared), nice, pretty, wonderful; boring, interesting, dangerous, safe; short, tall, long; new, old; calm, clear, dry; fast, slow; finished, free, full, light (=not dark), open, quiet, ready, strong.
Personal: afraid, alone, angry, certain, cheerful, dead, famous, glad, happy, ill, kind, married, pleased, sorry, stupid, surprised, tired, well, worried, young.
arrive, ask, be, be able to, become, begin, believe, borrow, bring, buy, can, change, check, collect, come, continue, cry, do, drop, eat, fall, feel, find, finish, forget, give, going to, have, have to, hear, help, hold, hope, hurt (oneself), hurt (someone else), keep, know, laugh, learn, leave, lend, let (=allow), lie down, like, listen, live (=be alive), live (=reside), look (at), look for, lose, love, make, may (=permission), may (=possibility), mean, meet, must, need, obtain, open, ought to, pay, play, put, read, remember, say, see, sell, send, should, show, shut, sing, sleep, speak, stand, stay, stop, suggest, take, talk, teach, think, travel, try, understand, use, used to, wait for, walk, want, watch, will, work (=operate), work (=toil), worry, would, write.
PRONOUNS (about 40 words)
Personal: I, you, he, she, it, we, they, one; myself, yourself, himself, herself, itself, ourselves, yourselves, themselves.
Possessive: mine, yours, his, hers, its, ours, theirs.
Demonstrative: this, that.
Universal: everyone, everybody, everything, each, both, all, one, another.
Indefinite: someone, somebody, something, some, a few, a little, more, less; anyone, anybody, anything, any, either, much, many.
Negative: no-one, nobody, nothing, none, neither.
Place: here, there, above, over, below, in front, behind, nearby, a long way away, inside, outside, to the right, to the left, somewhere, anywhere, everywhere, nowhere, home, upstairs, downstairs.
Time: now, soon, immediately, quickly, finally, again, once, for a long time, today, generally, sometimes, always, often, before, after, early, late, never, not yet, still, already, then (=at that time), then (=next), yesterday, tomorrow, tonight.
Quantifiers: a little, about (=approximately), almost, at least, completely, very, enough, exactly, just, not, too much, more, less.
Manner: also, especially, gradually, of course, only, otherwise, perhaps, probably, quite, so, then (=therefore), too (=also), unfortunately, very much, well.
CONJUNCTIONS (about 30 words)
Coordinating: and, but, or; as, than, like.
Time & Place: when, while, before, after, since (=time), until; where.
Manner & Logic: how, why, because, since (=because), although, if; what, who, whom, whose, which, that.