If you know 1000 of the most common words in your target language
then you should be able to speak the language quite well. (There are
many words in English that you know and recognise but have never
spoken.) The most common 1000 words make up between 80 and 90 per
cent of normal speech. You can certainly achieve a basic vocabulary of
1000 words in your target language within two weeks. When you have a
basic vocabulary, it is not difficult to pick up the other words you need.
You have a foundation to build on. You can get by superbly well in a
language with the most common 3000 words — and learning 3000 words
is not an impossible task.