Nice effect this Pareto effect.
Let me add that with 20% of the words, or vocabulary,
about 80% of a language is accessible.
Studying something is never finished though.
When the time is right, it is always nice to dive deeper into it.
Just for the record,
Study 10 words per day & within a year, about 30% of a little dictionary is covered.
The big dictionary of 100,000 or more words, might take a lifetime or more...
Cheers