There are some previous incidents of English Scrabble champions who didn't speak English (by the same approach of memorizing dictionaries without necessarily knowing the meaning of the words).

Here's a documentary about Thai Scrabble experts who often don't speak English:

https://www.youtube.com/watch?v=OyFJTEOHdi4

I believe there were also non-English-speaking competitors from other countries who had turned in world champion-level performances!