Quenya Phonetics P15: [ɸ], [β] became [f], [v]
Q. [ɸ], [β] became [f], [v]; [ɸ|β] > [f|v]
In Quenya the bilabial spirants ꝑ, ƀ [ɸ, β] (as derived from primitive ph, b) both became labio-dental f, v. These sound changes were mentioned in both the Outline of Phonetic Development [OP1] from the 1930s and the Outline of Phonology [OP2] from the 1950s: