frog

frog - O.E. frogga, a dim. of frox, forsc, frosc "frog," from P.Gmc.
*fruska-z.
actual forms:
German: frosch
Norwegian: frosk
Albanian : bretk ( masculine bretk, feminine bretkosë)
Romanian : brosc- ( feminine 'broasca', masculine 'broscoi')

The Latin form was "rana" ( but there is "ruscus"= toad, with an unclear
etymology), the Greek word is "bathrakos"
It seems that the originar form was with "br-" since the Germanic "f" is
originated more later and a Germanic "f" should be improbable to give an
"b" in Greek, Albanian and Romanian.
I am not sure if Greek "bathrakos" is a derived from the same root.
If the Greek word is from the same root, how are to explain the
differences here ?
germ:frosc
alb: bretk
rom: brosc
greek:bathracos
The Greek form has an "-ath-" between "b" and "r"; the Albanian has an
"-etk" instead of an "-osc" like in Germanic and Romanian.
Which should be the root in this case?