"chal wIleghlaHbe'. naDev Qorwaghmey tu'lu'be'."

Translation: We cannot see the sky. There are no windows here.

[phuvtuo]

why isn't it lutu'lu'be'?

[jdmcowan]

tu'lu' is a very special form that has become partially fossilized. By the rules of grammar the lu- prefix should be required, but it has been explained that Klingons often use tu'lu' even for plurals. In Duolingo's translations from English to Klingon, we accept it either with or without the lu- prefix.

[mizinamo]

I've heard some compare lutu'lu' to English's whom -- technically correct but used less and less by native speakers, and so tu'lu' (and who) has become accepted as correct.

[phuvtuo]

OK, that makes sense. I am glad to know that. Thank you as always.