Obviously it may have limited application to Welsh, because it’s particularly about English, but this is interesting. Perhaps an argument in support of patterns over vocab (speaking as someone who has never been naturally inclined that way).
Interesting stuff indeed, and supports discussions on the forum about a vocabulary of about 4K words being sufficient to conduct regular, normal conversations in Welsh. And Aran has this on the long list of things to do, I believe.
So it’s there an actual list of words in order somewhere?
Very interesting of course, but I think the frequency of any given word would depend upon which collection of data you choose to look at.
Professor Alexander Arguelles has made some interesting video lectures talking about this sort of thing, e.g. taking a series of books of different levels of difficulty (e.g. Pinnochio vs Moby Dick) and working out how big a vocabulary you would need in order to read them effortlessly.
In order to read what he refers to as “great books” [edited from “good books”] you need a pretty large vocabulary: a lot more than 4,000 words.
But of course, it depends on why you are learning the language and what you want to do with it in the long term.