Nonstandard African-American varieties of English have been stereotypically associated with a lower level of education and low social status. Since the 1960s, however, linguists have demonstrated that each of these varieties, and namely African-American Vernacular English, is a "legitimate, rule-governed, and fully developed dialect". The techniques used to improve the proficiency of African-American students learning standard written English have sometimes been similar to that of teaching a second language. Contrastive analysis is used for teaching topics in African-American Vernacular English. Both the phonological and syntactic features of a student's speech can be analyzed and recorded in order to identify points for contrast with Standard American English. Another way AAE can be taught is based on a strategy, communicative flexibility, that focuses on language used at home and analyzes speech during dramatic play. Using this method, children are taught to recognize when SAE is being used and in which occasions, rather than conforming to the speech around them in order to sound correct.