(Fossilization occurs when language errors become a permanent feature. See Canale & Swain (1980), Johnson (1992), Selinker (1972), and Selinker and Lamendella (1978).) The difference between learners may be significant. As noted elsewhere, L2 learners rarely achieve complete "native-like" control of the second language. For L2 pronunciation, there are two principles that haven been put forth by Levis (2005). The first is nativeness which means the speaker's ability to approximately reach the speaking pattern of the second language of speakers; and the second, understanding, refers to the speaker's ability to make themselves understood. Being successful in learning a second language is often found to be challenging for some individuals. Research has been done to look into why some students are more successful than others. Stern (1975), Rubin (1975) and Reiss (1985) are just a few of the researchers who have dedicated time to this subject. They have worked to determine what qualities make a "good language learner" (Mollica, Neussel, 1997). Some of their common findings are that a good language learner uses positive learning strategies, is an active learner who is constantly searching for meaning. Also a good language learner demonstrates a willingness to practice and use the language in real communication. He also monitors himself and his learning, has a strong drive to communicate, and has a good ear and good listening skills (Mollica, Neussel, 1997). Özgür and Griffiths have designed an experiment in 2013 about the relationship between different motivations and second language acquisition. They looked at four types of motivations—intrinsic (inner feelings of learner), extrinsic (reward from outside), integrative (attitude towards learning), and instrumental (practical needs). According to the test results, the intrinsic part has been the main motivation for these student who learn English as their second language. However, students report themselves being strongly instrumentally motivated. In conclusion, learning a second language and being successful depend on every individual. In pedagogy and sociolinguistics, a distinction is made between second language and foreign language, the latter is being learned for use in an area where that language is originally from another country and not spoken in the native country of the speakers. And in other words, foreign language is used from the perspective of countries; the second language is used from the perspective of individuals. For example, English in countries such as India, Pakistan, Sri Lanka, Bangladesh, the Philippines, the Nordic countries and the Netherlands is considered a second language by many of its speakers, because they learn it young and use it regularly; indeed in parts of southern Asia it is the official language of the courts, government and business.