"But in 'ballet' one doesn't. Or 'duvet' or 'gilet'.

There's no one rule fits all!"

I think English is pretty near impossible S. English is the only language I speak but I make mistakes. I can't think of an example off hand but it could be a word I've learned from ("simple" - Rufus and Everyman is about as far as I go) crosswords. You say the word and get corrected...

I can't remember much of my O level French but of the other language where I know a few words, I can get things wrong but I'd say Welsh can be easier than English - a few rules and you certainly would not be making a stab at a village I lived in being "Pie Dew" or the house I live in being "Co-ed Fa". They complicate things with mutations (which I gather are natural to a first language speaker but I've never got my head round) though.
https://en.wikibooks.org/wiki/Welsh/Mutations