20Speakers of any dialect of English who reside for a long periods of time in a region where a different dialect is spoken normally converge themselves to the speech; upon returning to their home region, they converge back to their native dialect. This is called _________.
(A)speech accommodation
(B)cooperative principles
(C)language shifting
(D)code switching

(A)speech accommodation 語言調適
(B)cooperative principles 合作原則
(C)language shifting 語言更替
(D)code switching語言碼置換

 In linguistics, accommodation is the process by which participants in a conversation adjust their accent, diction, or other aspects of language according to the speech style of the other participant. Also called linguistic accommodation, speech accommodation, and communication accommodation. 

 语言更替（Language shift）是指个人或社区原来习惯使用的语言被另一种语言所替代。这种替代常发生在属于少数民族的移民身上，其过程一般在三代人内完成  

 How many times do you want me to tell you, don’t be such a 雞婆（台語）.You see! For nothing, you were scolded by people.所謂語言碼置換（code switching），就如前面所舉出的幾個例子，是指兩種或兩種以上的語言夾雜出現的情形。這樣的說話方式，主要成因有二：第一是說話者在對某些用詞進行思索時遭遇到困難，想不起來要怎麼說，但是剛好有另一種語言的用詞可以補位，就會出現兩種語言共同合作演出的情況。當然，這種說話風格不一定只會出現在母語和第二語之間，母語和方言之間的交互運用更是時有所見。例如在台灣，常常都可以聽到人們夾雜使用中文和台語，一會兒說中文，一會兒說台語，偶爾台語說到一半，詞想不出來，就馬上改用中文來說。