Peter Nielsen Ladefoged (/ˈlædɪfoʊɡɪd/ ⓘ LAD-if-oh-ghid,[1] Danish: [ˈpʰe̝ˀtɐ ˈne̝lsn̩ ˈlɛːðəˌfoːð̩];[2] 17 September 1925 – 24 January 2006) was a British linguist and phonetician.

[4] Peter Ladefoged was born on 17 September 1925, in Sutton (then in Surrey, now in Greater London), England.

He also was interested in listening to and describing every sound used in spoken human language, which he estimated at 900 consonants and 200 vowels.

On May 5, 1970, Ladefoged was arrested and sustained injuries from police while participating in an anti–Vietnam War protest at UCLA.

[14] Ladefoged died on 24 January 2006 at the age of 80 in hospital in London, England after a research trip to India.