From Bakhtin’s perspective, communication is a dynamic and dialogic meaning-making process. It is situated in certain social-historical contexts, where languages act as cultural means to mediate thoughts among individuals. Hence, the feature of real language I think is authenticity.
On one hand, authentic language is context-dependent, which is influenced by the specific social and historical factors of the circumstance where people are situated. For example, Chinese people say 恭喜发财（Gong Xi Fa Cai, which means wish you to be prosperous in the coming year.）to each other during the Lunar New Year, which is one of the most common New Year wishes 2014 is the year of the horse in Chinese animal zodiac and lots of people will use some idioms with “horse”, 马(Mǎ), to send family members and friends good wishes, such as一马当先，马到成功 (yi ma dang xian, ma dao cheng gong). Taking the lead and achieving success, horses 马，Mǎ is a perfect combination of power and beauty, which represents speed and strength in Chinese culture. Even Chinese people regards horses as the dragon on the earth. In sum, the utterance of “恭喜发财, 一马当先，马到成功!” is unique due to the cultural-historical context: the lunar new year and the year of the horse, so people use these idioms to express good wishes to the interlocutor.
On the other hand, the individuals make the languages they use authentic. You mean hear "Gong Xi Fa Cai" (pronunced like "gong she fa tsigh" in English) in Mandarin and "Gong Hey Fat Choy" in Cantonese during the lunar new year in China. Even though the pronunciations are a little different, both are written the same way: 恭喜发财. Mandarin Chinese is the official language in China, which is regarded as the standard and prestigious means of communication. However, there are eight major dialects as well. Hence, don’t be surprised if you hear Chinese people from different parts of China talk differently. Probably, people from one side of the mountain might speak a totally different dialect than the people from the other side of the mountain. Dialects represent the local culture and shapes the locals’ identity. When people meet each other, they might use the mandarin with their own accents to greet each other and then they might discuss the topics they are both interested in, which is shaped by each individual’s perspective. Since people all have different life experiences, their perspectives are valuable because of the uniqueness of their personal understandings towards life.
All in all, the authenticity of language relies on both the cultural-historical context and the perspectives of individuals within in it.