"The fat, dirty dog slept in the street."
Translation:La dika, malpura hundo dormis en la strato.
Yes, I agree. In Esperanto we have to use the prepositions literally. The dog is nog "in" the street, the dog is "on" the street. Hence "sur la strato".
This made me think of The Colour Purple:
"You a low down dirty dog, that's what's wrong. Time for me to get away from you, and enter into Creation. And your dead body'd be just the welcome mat I need."