Found this bit about Black Speech especially fascinating:
Bear wrote:
Most often sung by low choral singers, Sauron’s Theme text is always set in Tolkien’s Black Speech. In Tolkien’s writings, as well as Peter Jackson’s films, the use of Black Speech has a sinister, magical effect, creating what Tolkien described in The Fellowship of the Ring as “a menacing … shadow … harsh as stone” around those hearing it. When recording sessions for The Rings of Power began, I felt the same ominous effect at the Synchron Scoring Stage every time our choir sang the Sauron Theme.
Dialect coach Leith McPherson recorded detailed pronunciation guide tracks for every cue and articulated clearly how important the consonants were to Black Speech. After they studied Leith’s pronunciation, the choir recorded the first take. Their performance was shockingly louder than the music notation requested. To pronounce the words properly, the singers intuitively felt it necessary to increase the aggression and the volume of their voices. Tolkien’s language itself changed the way the choir sang my music!