A method to practice English:

First, master the Ogden 850 basic vocabulary, then train or use an AI agent to converse with you using only these 850 words. This way, you won't be interrupted by big words, new words, or complex expressions when listening, speaking, or understanding, allowing you to enter real communication faster.
Once you can use the 850 words more naturally, gradually upgrade to the Oxford 3000 vocabulary to expand your range of expression and comprehension skills.