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We’re exploring why sometimes tones are different when written and when pronounced. Read on to learn why there are tone changes in Mandarin and what tone sandhi is all about!

When you’re learning a new language, being curious is a great quality to possess. We’ve decided to debut a new type of posts: Ask Nincha, where we share and answer questions our Chinese learners have asked us. This week, thanks to Philippe, we’ll see the tone sandhi. Challenging what you see, trying to understand why things work this way and not another is often the best way to make discoveries. In fact, questioning what you’ve learned and seeking patterns quite frequently leads to breakthroughs in your learning. Our learners at Ninchanese know that and therefore don’t hesitate to ask us questions using our feedback form. This week, Philippe, a Nincha Chinese learner, wants to know:

Why is 不 in 不要 and 不错  pronounced bu2 and not bu4 as written?

That’s a great question, and Philippe has a good ear! Sometimes the tones you see written differ from the tones you hear pronounced and that’s what’s happening here. The 不 in 不要 (bù yào – don’t) and 不错 (bù cuò – right) is pronounced bú (bu2) and not bù (bu4) as it normally is.

Why is that? Because tones don’t behave the same when you say several words together and when you just say one word by itself. The fact is tones change when used in combination. This fact is called tone sandhi.

For example, if our friend 不 here is followed by a second 4th tone (like 要 here, for instance), then the first 4th tone is automatically transformed into a second tone. Whatsmore, 不 is a special fella and has its own set of rules, which we’ll see below. 

Hang on, tone changes?

Before we go into the specifics of how tones can get modified, you may be still processing the fact that sometimes tones change in conversation and that a term like tone sandhi exists.

First, learning tone sandhi (aka the rules governing tone changes) is essential in Mandarin Chinese. Why is that? Because most of the time, you won’t find yourself only saying one word. You’ll be, most likely, saying a sentence, or at least a group of words. That’s usually what a normal conversation sounds like. It’s, therefore, a good idea to learn how tones behave in a sentence or a phrase.

So, It’s essential to grasp that what you know about the individual tone of a character will probably be different when you combine that character with another one to form a word. That’s why understanding the influence tones have on each other is an important step in your Chinese learning. It’s also key to speaking Chinese correctly.

3 rules to know

The first piece of good news is that modifications of tones follow rules, which are pretty simple to learn.

The second piece of good news is that while Mandarin has a number of instances of tone sandhi, there are only a few essential tone sandhi rules to master. Such as knowing some tones cannot stand being next to a similar tone, and would rather change than be the same as their neighbor. Chinese Tones are like that; you can’t question their personality. You just need to accept it.

If you’re ready to do that, great. Let’s dive straight into the tone changes you need to know when saying tones in combination/conversation.

一 and 不 both follow special tone rules

Two well-known tone sandhi rules involve the extremely common characters 一 and 不. In isolation, 一 and 不 have different tones. 一  is written yī (first tone) and 不 is written bù (fourth tone), but they are two special fellows who follow the same sets of rules.

Both 不 and 一 change their original tones when they meet a fourth tone. We’re not quite sure what’s up with the fourth tone, but it sure sounds like this falling tone doesn’t sit well with some characters. 不 and 一 definitely like being different, you see. Therefore, the Chinese have nicely decided to allow 不 and 一  to ditch their original tones and change them to second tones if they are followed by a fourth tone.

In short: for 不 , Bù changes to bú before another fourth-toned syllable, like so: 4–4 → 2–4. For 一, yī changes to yi2 when it’s followed by a fourth tone, like so:  1-4 → 2-4.

That’s why, as Philippe noticed, the 不 in  不要 or 不错 is pronounced bu2 and not bù (bu4). The tone sandhi rule for 不 followed by a fourth tone is applied.

Here are a few more examples:

不对 (not correct) is written bù duì (bu4 dui4) but is pronounced bú duì (bu2 dui4)
不必 (not necessarily) is written bù bì (bu4 bi4) but is pronounced bú bì (bu2 bi4)

In a similar way, 一 changes its first tone into a second tone:

一个 (one) is written yī gè (yi1 ge4) but is pronounced yi2 ge4
一共 (altogether) is written  yī gòng (yi1 gong4) but is pronounced yígòng (yi2 gong4)

不 and  一 can also be neutral

Now that you know that the angry 不 with its aggressive fourth tone and the flat-lining  一 with its first turn can both turn into a second tone, let’s add a twist. Neutral zone!

See, when “不” followed by a fourth tone BUT comes between two words in a yes-no question, it loses its tone. That’s right, bù becomes bu, neutral in tone, in some cases, rather than turning into a second tone.

是不是 (is or is not) is written shìbùshì but becomes shìbushì in speaking

The same thing happens to 一 who can also change to the neutral tone, depending on the speaker or the discourse style.

一个  can become yi gè, for example.

So how do you know which rule to apply? A way to keep this in mind is to think about the context: is the word here being emphasized in the conversation?

If yes, opt for a second tone.

If not, it’s an unstressed part of the sentence, and as a result, it loses its tone. This is frequently the case in natural conversation in Mandarin.

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An exception to the tone sandhi rules for 一

You’ll run into exceptions in tone sandhi for  一when you’re using the number 1 in a counting sequence or as part of another word. In these cases, it remains a first tone.

一月 (January) is written yī yuè (yi1 yue4) and remains pronounced yī yuè (yi1 yue4), despite the following fourth tone.

Third tone: a more complex tone that you think

Third tones are often learners’ favorite tones, because, on its own, a third tone’s rising and falling pitch is instantly recognizable. This usually makes the third tone the easiest of the 5 tones to recognize, at first. However, things get hairier when you realize third tones are far from being this simple, especially when they have company. Let’s just start talking about changes in third tones by saying that a whole chapter could be dedicated to third tones and their behavior. In fact, some actually dedicated their memoirs to the changes in this tone.

Third tone changes when in pairs

We’re going to try to make it short here and give you a concise picture of what goes on with third tones. We still want you to like third tones, after all, so let’s try to make this explanation as simple as it can be.

• If a third tone is followed by another third tone,  the first third tone becomes a rising “half third” tone. Technically, you just pronounce the rising first-half of the third tone but for simplification purposes, it’s often said that it becomes a second tone.

For example, 你好 (hello) is written nǐ hǎo (ni3 hao3) but it’s pronounced ni2 hao3
很好 (good) is written hěn hǎo (hen3 hao3) but it’s pronounced hen2 hao3

• When a third tone is followed by any other tone, it often transforms into a low, falling “half-third” tone.

Third tone changes when in triples and more

• If there are three third tones in a row, tone sandhi rules of third tones  get more complicated. For instance: In a string of words all with third tones, if the first word is two syllables, and the second word is one syllable, the first two syllables become second tones, and the last syllable stays a 3rd tone.

保管 好 (to guarantee well) is written bǎoguǎn hǎo but becomes bao2guan2 hǎo.

Then again, how the tones behave depends on how you break down the string of words and a number of other things. So, based on who you speak to and what words you pick, you may hear different rules. The truth is the way the third tones behave depends on several variables we won’t go into here. What you need to remember is that in most cases, the third tone will behave as a low tone and that as long as you mimick what natives say, you should be okay. Learn more about the third tone here and here.

Tone Contours, courtesy Sinosplice and Grammar Wkiki

One last tone sandhi rule we could talk about here is quiet second tones. See, in some cases, the second character in a word loses its tone and becomes neutral, like in 爸爸. But quiet second tones are a fascinating and complex subject we won’t go into details here yet. We’ll be telling you about them soon, though.

 How do you know when to apply tone changes?

Are you wondering when to apply tone changes? And perhaps how to spot if there’s been a tone change applied? Good questions to be asking yourself.

First of all, the standard is to always make that tone change when speaking. It’s a given: if you’re saying more than one syllable at a time, mind your tone sandhi switches. This is why in Ninchanese our audio automatically includes tone changes. In writing, the

Second, that’s not the case in writing. In writing, the characters and sentences you learn do not follow tone changes, and that’s the norm. Why is that? There’s no simple way to indicate whether the tone you’re reading follows or not tone sandhi (i.e those tone changes we’ve been telling you about). So, it’s standard to not change tones in writing. That means you are expected to automatically make the changes in your head when you speak and read a sentence. Now you know.

Getting used to thinking about tone sandhi rules

Getting used to changing tones — in your head — can take some time, let’s be blunt. The main issue resides in the fact you have to think about the fact you’re going to be stringing two or more characters together and therefore will be needing to apply tone changes. But don’t worry and by all means, don’t keep yourself from talking if you’re not sure what rule to apply! It’s something you learn with time.

Yes, believe our experience, with time, applying tone sandhi can become as automatic as knowing when to say “a” and “an” in English.

A summary of the major tone sandhi rules to know

Feeling ready to start changing your tones in natural conversation in Chinese? Good. Before we leave you, here’s a summary of the different behaviors tones can adopt based on what they’re followed by.

Now you know that tones aren’t always very open, and sometimes want to show a different face to others.

A visual summary of tone changes when in pairs – credit: Hacking Chinese

We hope these explanations will have helped you understand better what tone sandhi is about and when you need to think about changing your tones in conversation in Mandarin. As often, practice, practice, and mirroring others (native speakers preferably) is the best way to fully master tone sandhi changes. Do you have any questions about tone sandhi or specific tone changes? Let us know in the comments and we’ll gladly answer! Also, if you want to #askNincha your own Chinese related question, head here and fire away! 

Sarah, a meowsome member of the

The Nincha Team

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