Vocabulary is not learned word-by-word.
It is acquired network-by-network through many meaningful encounters over time.
Fluency is largely the result of
knowing many high-frequency words
knowing them deeply
recognising them easily
using them automatically
That is why a system focused on
the 5000 most common words
comprehensible stories
repeated exposure
collocations
active retrieval
is one of the strongest possible foundations for language acquisition.