sì shēng diào xué hàn yǔ, 四声调学汉语, Learn Chinese with Four Tones。
例字：
bā, 八, eight。
bá, 拔, pull。
bǎ, 把, put。
bà, 爸, dad。
声调不仅在现代汉语占有极重要的地位，就连在古音中也一样，古时汉语的声调有多少类，自来言人人殊，纷纭无定。中国传统音韵学上一向所谓的“四声”，都是声调分为把声调分为“平”、“上”、“去”、“入”四类，这情形至少在五世纪前就已经存在。
Tones play a very important role not only in modern Chinese, but also in ancient Chinese. There are many different kinds of tones in ancient Chinese. The so-called “four tones” in traditional Chinese phonology are divided into four types of tones: “ping”, “shang”, “go”, and “ent”. This situation has existed at least before the fifth century.
据《梁书·沈约传》记载：“约撰四声谱，以为在昔词人，累千载而不悟，而独得胸衿，穷其妙旨，自谓入神之作。高祖雅不好焉，帝问周舍曰：‘何谓四声？’舍曰：‘天子圣哲是也。’”于是，“平、上、去、入”四声之名由是确定。这种把语音的声调按照它的读法不同而为“平声”、“上声”、“去声”、“入声”的传统分类法，称为“调类”。
According to the “Liang Shu·Shen Yue Biography”: “Yue wrote four-tone scores, thinking that in the past, the poets had not realized it for thousands of years, but he had only got his chest, and was poor in his wonderful purpose. He said that he was a masterpiece. Okay, the emperor asked Zhou She: “What are the four tones?” She said: “The emperor’s sage is also.”” Then, the name of the four tones of “ping, going up, going, and entering” was determined. This traditional classification of the tones of a voice as “Ping Sheng”, “Shang Sheng”, “Qu Sheng” and “In Sheng” according to its pronunciation is called “Tune Class”.
隋、唐的切韵，宋代的广韵也都把声调分为“平”、“上”、“去”、“入”四种，叫做“四声”。后来，各地的语音大体上都还保留着这个中古时期的四声系统。但语言不论是语音、语词、语法都会随着时代的推进而改变。
The Qie Yun of Sui and Tang, and Guang Yun of the Song Dynasty also divided the tones into four types: “Ping”, “Shang”, “Go”, and “Enter”, called “Si Tone”. Later, the phonetics in various places largely retained the four-tone system of the Medieval period. But the language, whether it is phonetics, words, or grammar, will change with the progress of the times.
以声调来说，到了元朝周德清的中原音韵以后，北方语音的“平声”就已经分化成两类，就是“阴平”跟“阳平”。其演变的规律，大体上是：古音属于清声母的字，现代都念作“阴平”；古音属于浊声母的字，现代都念作“阳平”。这也就是北平话的“平声”所以分为“阴平”跟“阳平”的原因。至于“上、去、入”三声在其他各地也有些分化为阴阳二类的现象，所以有“阴平”、“阳平”、“阴上”、“阳上”、“阴去”、“阳去”、“阴入”、“阳入”等调，如潮州话。有些地方则“上声”不分阴阳，如闽南语泉漳片、福州话、客家话等，所以这些方言各有七个声调。因此各地方言的声调，多寡不一，有的少到三个（如河北滦县），有的多至十个（如广西博白县）。
In terms of tone, after the Yuan Dynasty Zhou Deqing’s Central Plains phonology, the “ping sound” of the northern voice has been divided into two types, namely “yinping” and “yangping”. The law of its evolution is roughly as follows: the ancient sounds belong to the characters of the clear consonants and are pronounced as “yinping” in modern times; the ancient sounds belong to the characters of the voiced initials and are pronounced as “yangping” in modern times. This is why the “pingsheng” in Peking dialect is divided into “yinping” and “yangping”. As for the three tones of “going up, going, and entering” in other places, there are some phenomena that are divided into two types of yin and yang. Tones such as “go”, “yin enter”, “yang enter”, such as Chaozhou dialect. In some places, “Shangsheng” does not distinguish between yin and yang, such as Quanzhang, Fuzhou dialect, Hakka dialect, etc., so these dialects each have seven tones. Therefore, the tones of each local dialect vary in number, some as few as three (such as Luan County, Hebei), and some as many as ten (such as Bobai County, Guangxi).