"You are saying the word wrong."
Translation:Říkáš to slovo špatně.
Something I don't quite understand is that "the" should be kind of not needed in Czech unless we want to stress it (at least this was my understanding). In this case I write "Říkáš slovo špatně" and DL corrects me saying the right answer is "Říkáš to slovo špatně". Is it wrong because it is meant that it was that specific word that was wrongly said? Thus, the "the" is needed in Czech. Or is there a rule I missed that indicates when to use the "the" in Czech?
That is not really correct. Czech requires a demonstrative (and a Czech demonstrative is not the same as an English definite article) when it is not clear which specific entity it is. If we have only one dog, we can say "Pes je doma." and we know we mean "the dog", the only dog around. But there are many words, it is unlikely "slovo" would be understood as "the word" unless perhaps used in some religious meaning.
Be aware that various languages differ in this point and Czech uses the demonstratives much mar than, e.g., Russian.