That work distinguished langue from parole.
He theorized the existence of laryngeals while still a student, and he described the development of the vowel a in Memoir on the Original System of Vowels in the Indo-European Languages. He also developed the idea of the linguistic sign and signifier. His most influential work helped to establish structural linguistics; however, it was compiled and published by Charles Bally and Albert Sechehaye. That work distinguished langue from parole. For 10 points, name this Swiss guy whose notes were compiled into the posthumous Course in General Linguistics.
He theorized the existence of laryngeals while still a student, and he described the development of the vowel a in Memoir on the Original System of Vowels in the Indo-European Languages.
Ferdinand de {Saussure}