Linguists have known for decades that a relatively small set of words makes up the vast majority of everyday language use. The Oxford 3000, the General Service List, and other frequency-ranked word lists all point to the same conclusion: master around 500 high-frequency words and you can understand approximately 90% of everyday spoken and written English.
This isn't a shortcut — it's strategic learning.
The most frequent 100 words in English are almost entirely grammatical: the, be, to, of, and, a, in, that, have, it. These aren't exciting to learn, but they're the scaffolding that holds everything else together. If you hesitate on any of these, fluency suffers.
The next 400 words cover the most common verbs, nouns, and adjectives in daily conversation: say, go, come, time, year, good, big, new, want, think.
How to learn them effectively: Don't study lists in isolation. Encounter each word in multiple contexts — reading, listening, speaking. Use spaced repetition software like Anki to review them efficiently. And crucially: pay attention to how words combine. 'Make' collocates with 'a decision', 'a mistake', 'a difference' — knowing this is worth more than knowing ten synonyms for 'make'.