Rohirric

Rohirric is derived from the language of the Éothéod, who were among the Northmen and was related to other Northmen languages, such as those of Rhovanion, Esgaroth, and Dale.
The Hobbits before their Wandering Days in the Vales of Anduin had contact with that people and their languages had many words in common. For example the Rohirrim had retained the legend of the being known as kûd-dûkan (translated as hol-bytla), a term which became kuduk by the Hobbits, the name they had for themselves.
Many archaic Hobbit names bear similarities to Rohan's, since the ancestors of The Shire hobbits lived on the upper reaches of the Anduin, close to the ancestors of the Rohirrim, and there was apparently a good deal of linguistic cross-fertilisation.
Despite its relation to Westron, the Rohan language was not intelligible to its speakers. Legolas was unable to understand the songs, however he noted that the language is like the land itself: rich and rolling in part, and else hard and stern as the mountains.