In English there may be hundreds of thousands to millions of words. Of course it’s difficult for beginners who want to learn English to memorize hundreds of thousands of words to build vocabulary.
First because this requires a very long time.
Second, because this is a waste of time. Even native speakers themselves do not memorize hundreds of thousands of words.
Linguists conclude that of the hundreds of thousands of words in English, only around 2000 to 3000 words are commonly used in everyday life. Therefore, if you want to start learning English or are developing English, you can start by studying 3000 words slowly. Thus, it can build vocabulary and be able to use English to communicate.
Oxford builds a list of the 3000 most common words above in their dictionaries.