汉语是一个语族，包括了七大方言，其中普通话和粤语是世界上通行范围比较广的两种汉族语言。汉语属汉藏语系，而普通话是这个语系里的通用语言。影响范围除了中国大陆、香港特别行政区、澳门特别行政区和台湾地区以外，普通话还分布在新加坡共和国、马来西亚等国。会说普通话的人大约有14亿（3000万人作为第二语言）。普通话是联合国承认中国官方的工作语言之一。

“汉语”it's a language, and "普通话" it's a language accent or pronunciation accent , "汉语" including many local dialect , but "普通话" it's the national language .

中文=汉语=Chinese, which has a long history and is very diversed ,汉语 is the language of ethnic Han——the most of Chinese people are Han. 普通话：particularly indicates the Offical language of China.It is used by most of Chinese people. The government of PRC began to promote mandarin during 1950s, calls for all chinese people to speak and wirte a uniform and standard language based on beijing dialect. recommend you a short film (about 10 minutes) introdusing China http://www.tudou.com/programs/view/zb84YZR--2w/

汉语 or 中文 refers to the chinese language with all the dialects, but 普通话 is the dialect of beijing and is the official dialect of china, as the official language to be on TVs and newspaper, like the english, u say (american english - british english - autralian english) and so on.. so mandarin is a chinese dialect

Sorry, 普通话 is based on Mandarin Chinese and is created in 1955.