Yes. There definitely lies copyright on any database established in the EU. A word frequency list is a database, and has a 15 year sui generis copyright. This also includes derivative works.
lightly remixing the wordlist counts as a derivative work, and falls under copyright protection.
The answer provided by "user6726" is incomplete. While automated frequency lists can be generated, they are usually error-prone. Raw data maybe can't be copyrighted, I'm not sure about that.
But a cleaned corpus is copyrighted. When tagging raw corpus data, there is a 35 to 5% inaccuracy in any automated text. This depends on the software used. This requires manual action, and it takes many hours to establish a reliable frequency list.
Especially Slavic languages, with their many inflections, prove quite difficult.
I can't comment on posts, but another user said something about using the same source text to establish a frequency list. It's very unlikely that a source is used multiple times. The frequency lists you get from analyzing a source text would vary vastly depending on the source text used.
It is very easy to spot when someone used a frequency list that they did not establish themselves if you have some experience building corpora/frequency lists.
Please see here for more information:
Source: I'm a publisher specializing in these kind of things.