darasteine:

The 75 most common words make up 40% of occurrences
The 200 most common words make up 50% of occurrences
The 524 most common words make up 60% of occurrences
The 1257 most common words make up 70% of occurrences
The 2925 most common words make up 80% of occurrences
The 7444 most common words make up 90% of occurrences
The 13374 most common words make up 95% of occurrences
The 25508 most common words make up 99% of occurrences

(Sources: 5 Steps to Speak a New Language by Hung Quang Pham)

This article has an excellent summary on how to rapidly learn a new language within 90 days.

We can begin with studying the first 600 words. Of course chucking is an effective way to memorize words readily. Here’s a list to translate into the language you desire to learn that I grabbed from here! 🙂

EXPRESSIONS OF POLITENESS (about 50 expressions)
     

• ‘Yes’ and ‘no’: 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, I’m afraid so, I’m 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, don’t mention it, sorry, it’ll be done, I agree, congratulations, thank heavens, nonsense.
     

NOUNS (about 120 words)

• 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. 0–20; nos. 30–100; nos. 200–1000; last, next, 1st–12th.
     
• 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.
     

VERBS (about 100 words)
   

• 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.
     

ADVERBS (about 60 words)

• 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.