There are several concepts and terminology to consider for the "Language of the Tokyo metropolitan area" (TMA). These concepts and terminology are similar yet also complicated. Therefore, I do not intend to categorize them. Rather, I argue the viewpoints that are adopted when considering them. When the traditional dialect forms declined after the 1980s, new dialect forms developed and attracted attention. Then, modified models were proposed instead of a simple standardization model. The background for these studies was influenced by the introduction of sociolinguistics to the dialectological world and changes in the population structure of Japanese society. The heartland of Tokyo (ex-Edo) is very small, and the areas called uptown/downtown spread into the adjacent area. Therefore, the TMA is more suitable for study compared to the heartland of Tokyo. Tokyo and the adjacent area are continuous in terms of the linguistic characteristics. Given the large population of immigrants in the TMA, traditional dialect forms are rarely used. To understand the language of the TMA, I propose five viewpoints: "standard language or common language," "public or personal," "dialect or slang," "consciousness or unconsciousness," and "understanding or use." We can consider these viewpoints in detail by applying the concepts of "New dialect" and "Neo dialect."