Nahaiduk

Nahaiduk is the language of the woodmen of Rhovanion.Like most rhovanian dialects it is usually represented by modified gothic.

speculations
Since the Name of the Rhovanian Wizard Radagast actually is a franconian form, as well as many Fallowhide Hobbits, notably members of the Took family, have franconian names, it is likely that Tolkien imagined the Woodmen-tongue to be related to the other Northron tongues in a way as franconian was related to anglo-saxon, old norse and gothic.

While the -duk element clearly is derived from gothic 'tuggo (tongue) the Nahai- Element seems obscure.It may be derived from anglo-saxon neah', so Nahaiduk would be the tongue of those who (are) near.A possible franconian form could be Natunga or Namantunga.