On the occasion of the 20th anniversary of the founding of the Sociolinguistic Society of Korea (SSK), the paper presents a brief retrospective aspect of the developmental history of SSK and a comprehensive overview of the Labovian theory of language variation and change. He is the first sociolinguist who introduced the quantitative method to analyze the linguistic variation. His Master’s thesis Martha’s Vineyard Study (1963) and his doctoral dissertation The Social Stratification of New York English (1964) indeed gave rise to the rapid development of sociolinguistics in late 60s as a counterforce to the popular activities of the theoretical linguistics. Labov’s efforts for the education of the low-income children in Reading also deserve to be included just as great contributions as his linguistic achievements. The three volumes of his Principles of Linguistic Change which have just been completed this year together with The Atlas of North American English which includes vowel changes and chain shiftings of 332 northern American cities to establish the phonology of North American English more or less sum up his life-time achievements of 50 years in research and teaching.

I. 서론
 II. Labov 교수의 약력과 근황
 III. Labov의 언어변이/변화이론의 배경과 형성 과정
 IV. 저소득층의 글읽기(Reading) 교육을 위한 연구
 V. 공항테러범 사건(The Prinzivalli Case)
 VI. 최근 20년간의 연구 업적(1990-2010)
 VII. 맺는 말

• 홍연숙(중국연변과학기술대학/한양대학교)