Chinese itself is spoken by over one billion people worldwide, about one-fifth the people in this world speaks Chinese as a native language, and some 95 percent of this Chinese population speaks Chinese, compared to the non-Chinese languages, such as Tibetan, Tai, Mongolian, Miao, and Lolo which are spoken by minorities.
The Chinese Dialects
In general, Chinese comprises of many regional variants, known as dialects. Each dialect group consists of a large number of dialects, which may be referred to as a language. The most spoken and known are considered under the Mandarin group of the seven in Chinese. The Cantonese dialect is also another of Chinese which is well known and spoken in Hong Kong, Guandong, Southern Guangxi Zhaung Autonomous Region, some parts of Hainan, Macau, and in many other overseas settlements throughout our world. The Hakka languages (a.k.a. Kejia) are found in areas like Fujian, Jiangxi, Junan, yunan, Guangxi, Guizhou, Sichuan, Hainan, Taiwan, Singapore, Malaysia, Indonesia, many overseas Chinese communities, and certain areas in Southeast Asia. Inhabitants of the south central region, in Hunan use a dialect known as the Xian dialects (Hunanese). Fujian, large areas of Taiwan and Hainan, certain parts of East Guangdong, the Leizhou Bandao Peninsula, and areas of Southeast Asia, speak the Min dialects. Many of the population living in Jianxi, eastern vicinity of Hunan, and the southeastern corner if Hubei use the Gan dialects. And last of all, another populous dialect, the Wu dialect, which is used in the majority of the population inhabitants of Zhejiang, in addition the many people living in southern half of Jiangsu and Anhui.

Click on the picture to have a larger view
Genetic Classification
Together with Tibetan and Myanmar (previously known as Burmese), Chinese and the tribal languages of South and Southeast Asia, belong to the family of Sino-Tibetan languages, which contain a core vocabulary and sounds. Besides that, Chinese and most related languages share certain features which differentiate them from most Western languages. These features include: monosyllabic that have little inflection and are tonal. So how are the words able to be told apart? The many languages of the family of Sino-Tibetan languages, in order to indicate differences in meaning between words similar in sound, assign tone languages to give a distinctive pitch.
Influences
The history of Chinese culture and politics both have had a great number of influences on related languages such as Korean, Vietnamese, and Japanese. Like the Chinese writing system, Korean and Japanese employ Chinese characters (Hanzi), which are called Hanja and Kanji respectively.
In Vietnamese, the term for Chinese writing is Han Tu and was the only for of writing until the 14th century, which was used exclusively by educated elites in Vietnam. From the 14th till the late 19th century, however, Vietnam was with Chu Nom, a modified Chinese script incorporating sounds and syllables for native Vietnam speakers, which is now replaced by modified Latin script with a system of diacritical marks to indicate the tones, as well as modified consonants. Mixed with some elements from Cantonese, Vietnamese is also influenced with Mandarin due to sharper vowels.
In South Korea, the Hangul alphabet is commonly used, but Hanja is used as a sort of boldface. (In North Korea, however, this has been discontinued.) Since the transformation of Japan in the late 19th century, some debates have occurred over abandoning the use of Chinese characters, but the practical benefits of a radically new script have so far not been considered sufficient.
It’s History
(Note: The development of the Chinese language is an often scholarly debated subject)
One of the first systems was devised by the Swedish linguist Bernhard Karlgren in the early 1900s. However, this system was much revised, but always heavily relying on Karlgren's insights and methods.
Old Chinese, sometimes known as 'Archaic Chinese', was the language common during the early and middle Zhou Dynasty (1122 BC - 256 BC), texts of which include inscriptions on bronze artifacts, the poetry of the Shijing, the history of the Shujing, and portions of the Yijing (I Ching). The phonetic elements found in the majority of Chinese characters also provide hints to their Old Chinese pronunciations. The pronunciation of the borrowed Chinese characters in Japanese, Vietnamese and Korean also provide valuable insights. Old Chinese was not wholly uninflected and possessed a rich sound system in which aspiration or rough breathing differentiated the consonants, but probably had no tones yet. Work on reconstructing Old Chinese started with Qing dynasty philologists.
During the Sui, Tang, and Song dynasties (7th through 10th centuries AD), Middle Chinese was used. Middle Chinese can be divided into an early period, reflected by the 切韻 'Qieyun' rhyme table (601 AD), and a late period in the 10th century, reflected by the 廣韻 'Guangyun' rhyme table. Linguists are confident of having reconstructed how Middle Chinese sounded. The evidence for the pronunciation of Middle Chinese comes from several sources. However, all reconstructions are tentative; for example, scholars have shown that reconstructing modern Cantonese from the rhymes of modern Cantopop would give a very inaccurate picture of the language.
The development of the spoken Chinese languages from early times to the present has been an extremely complex process. Most northerners Chinese people, in Sichuan and in a broad arc from the northeast (Manchuria) to the southwest (Yunnan), use various Mandarin dialects as their home language. The prevalence of Mandarin throughout northern China is principally due to north China's plains. Unlike southern China, mountains and rivers encouraged linguistic diversity. The presence of Mandarin in Sichuan is largely due to a plague in the 12th century. This plague, which may have been related to the Black Death, depopulated the area, leading to later settlements from north China.
Around the mid-20th century, most southern Chinese did not converse in any dialects of Mandarin. However, despite the mix of officials and commoners speaking various Chinese dialects, Nanjing Mandarin became dominant at least during the officially Manchu-speaking Qing Empire. Since the 17th century, the Empire had set up orthoepy academies to make pronunciation conform to the Qing capital Beijing's standard, but had little success. During the Qing's last 50 years, Beijing Mandarin finally replaced Nanjing’s dialect in the imperial court. For the general population though, variations of Mandarin were now widely spoken in China then, a single standard of Mandarin did not exist then. The non-Mandarin speakers in southern China also continued to use their regional dialects for every aspect of life. The new Beijing Mandarin court standard was thus fairly limited. The situation changed nevertheless as the creation of the elementary school began which committed to the standard Mandarin. As a result of this influence, the majority in mainland China now speak Mandarin fluently and in Taiwan. (An exception is Hong Kong, for its education and formal speech remains Cantonese.)
Standard Chinese
Mandarin is considered the official standard language in PRC, ROC, and Singapore, and is based on the Beijing, China dialect. All of these governments intend for speakers to use Mandarin as a common language out of all the dialect varieties for communication, therefore being used throughout government, media, and in school. Although, Singapore may be partly exempt for English is a more standardized language there.
Conclusion
Chinese is certainly the most populated language worldwide, if it is considered a language. It is even believed that Chinese may dominate English because of its fast growing economy. We may see in time. So what should we do in the meantime? Well, try learning Chinese…