Learning a new language may not be as difficult as you think

Research into language vocabularies shows that only about 3000 words are used on a daily basis actively. So by learning those 3000 words that are used frequently, you can quickly learn a new language. (Via Priya Raju) References:
1. Second Language Vocabulary Acquisition, linguistic context and vocabulary task design by Rob Waring. 2, Vocabulary Size, Text Coverage and Word Lists by Paul Nation and Robert Waring 3. 3000 Most Commonly used English words