"This lawyer does not speak clearly."
Translation:Ten prawnik nie mówi jasno.
Ten prawnik nie mówi czysto. I have repeatedly heard and used the word 'czysto'. 'jasne' I have always taken as 'of course!' or something similar. Like: "chcesz iść do basenu?" 'Jasne!'
I think "jasno mówi" would be more or less acceptable (although I'd definitely prefer "mówi jasno"), but as it's negated here, "nie jasno mówi" would be just wrong.
"niejasno mówi" (talks unclearly) would be on the same level of acceptability as "jasno mówi".