轻声和儿化
Neutral tone and erhua

“谢谢”你说过几百次了，第二个“谢”又短又轻，你从来没读成 xiè xiè。“朋友”“桌子”“我们”“好了”也一样，后面那个字轻轻地带过去。你还说过“一点儿”“这儿”“玩儿”，那个“儿”你也没当成一个字来念。这两件事就叫轻声和儿化。

You have said 谢谢 a few hundred times, and the second 谢 always came out short and light — never xiè xiè. 朋友, 桌子, 我们, 好了 behave the same way: the second syllable is carried across lightly. You have also said 一点儿, 这儿, 玩儿 without ever pronouncing that 儿 as a syllable of its own. Those two habits are called 轻声 and 儿化.

轻声不是第五个声调。它是一个音节失去自己的调以后剩下的东西：短、轻、听不出高低。所以“子”单念是 zǐ（上声），可是在“桌子”里读 zi，一点调都没有。

The neutral tone is not a fifth tone. It is what is left when a syllable gives up the tone it owns: short, light, with no shape you can hear. So 子 on its own is zǐ, a third tone, but inside 桌子 it is just zi, with no tone at all.

还有一大批双音节词，第二个字习惯上读轻声，得一个一个记：朋友 péngyou、东西 dōngxi、衣服 yīfu、时候 shíhou、意思 yìsi、喜欢 xǐhuan、明白 míngbai、便宜 piányi、学生 xuésheng。字典里这些字后面不标调号，就是告诉你读轻声。

A large set of two-syllable words simply take a light second syllable, and these have to be learned one by one: 朋友 péngyou, 东西 dōngxi, 衣服 yīfu, 时候 shíhou, 意思 yìsi, 喜欢 xǐhuan, 明白 míngbai, 便宜 piányi, 学生 xuésheng. When a dictionary prints the second syllable with no tone mark, that is the instruction.

这样的词不多，可是很常用，所以轻声不只是好听不好听的问题。“地道”也是一样：dìdào 是地下的通道，dìdao 是“很正宗”。

There are not many such pairs, but they are common, so the neutral tone is not just a matter of sounding smooth. 地道 works the same way: dìdào is a tunnel, dìdao means genuine, the real thing.

儿化是北方话、特别是北京话的特点，南方说得少，所以它是可多可少的：说“这里”“一点”也完全对。要注意的是拼音跟着嘴走：一点儿写 yìdiǎnr，可是说的时候中间的 n 已经不见了。有时候儿化还分词性：画 huà 是动词，画儿 huàr 是名词；盖 gài 是盖上，盖儿 gàir 是盖子。

Erhua is a northern feature, Beijing above all; southern speakers use far less of it, so it is largely optional — 这里 and 一点 are perfectly good. Note that the spelling follows the mouth: 一点儿 is written yìdiǎnr, but the n has already vanished when you say it. Sometimes erhua even marks word class: 画 huà is the verb 'to paint', 画儿 huàr is 'a picture'; 盖 gài is 'to cover', 盖儿 gàir is 'a lid'.