Here in Holland one refers to Mother's Day as "moederdag", without the letter s.

I keep calling it "moedersdag", with the letter s like it is called in English, but this is wrong.

For the life of me I cannot remember this subtle difference of a single letter, and keep on pronouncing it incorrectly.

"Moedersdag," sorry. I mean: Moederdag, moederdag, moederdag!