Hebrew most strongly influenced Tolkien’s creation of the Dwarvish language Khuzdul.
Khuzdul is the secret language of the Dwarves in Tolkien’s legendarium. Tolkien designed it with features that recall Hebrew, including elements of sound, word formation, and the use of consonantal roots. This influence helped distinguish Khuzdul from his Elvish languages, whose development drew more heavily on languages such as Finnish and Welsh.
The Dwarves generally kept Khuzdul private and used other languages when communicating with outsiders. As a result, Tolkien supplied far less recorded Khuzdul vocabulary than Quenya or Sindarin. Names and phrases such as Khazad-dûm and “Baruk Khazâd!” provide important examples.
Khuzdul is sometimes confused with the Black Speech of Mordor because both are associated with non-Elvish peoples. They are separate languages with different fictional histories and purposes in Tolkien’s world.