(Incidentally, Alexander Graham Bell's father, Alexander Melville Bell, was a phonetician.) During World War II, work at the Bell Telephone Laboratories (which invented the spectrograph) greatly facilitated the systematic study of the spectral properties of periodic and aperiodic speech sounds, vocal tract resonances and vowel formants, voice quality, prosody, etc.
Ernst W. Selmer (1890–1971), Norwegian philologist and phonetician
Eugen Dieth (November 18, 1893 in Neukirch an der Thur - Mai 24, 1956 in Zollikon) was a Swiss linguist, phonetician and dialectologist.
Jean-Pierre Rousselot (14 October 1846, Saint-Claud - 16 December 1924, Paris) was a French priest who was an important phonetician and dialectologist.