Ulagh

How is there the conenction of volcae, walah and
tartar/turcick "ulagh"?
Does it mean the tartar or turcks got the name from slavs too
? Or from germans?
I keep in mind here the work of persan scholar Fäzl ol Lah
Räsid about the tartar invasion of 1241
Teh tartar name of this is "Kara Ulagh"= black Walachia and
from otoman sources we know that the turkish name was Kara
Iflack.