I recently got an e-mail from a beginner regarding tones in Mandarin:
I was searching the web to find an answer with no luck. I read what you wrote about Debating “You’re Welcome” and I’m hoping you can help me.
I keep finding different sources giving different tones for “bu keqi”. In Chinese for Dummies bu has a rising tone and keqi both have falling syllables. Another book gave a falling tone to bu, a flat tone to ke, and a rising tone to qi. Many websites tell me that I have the right words, but they don’t give the tones at all.
If you have an extra minute, I’d also love to know the tones on the variants you wrote, or a good source to look them up at.
I realized that the author of the e-mail was confused because there is a rule in Mandarin Chinese that when when 不 precedes a 4th tone, it becomes second tone. Most textbooks will expect you to always remember this after they teach it, and will still mark 不 as 4th tone even though it should be read as 2nd tone. Some textbooks, however, mark 不 as 2nd tone when it should be read as 2nd tone. I can see how that could be very confusing to a new learner.
In responding, I wanted to include a link to a site which clearly outlined all the tones changes (AKA tone sandhi) that occur in Mandarin. I was disappointed that Wikipedia didn’t seem to have one. Eventually I found the rules outlined clearly in the Change of Tone section of a site called InstantSpeak Chinese.
I had never explicity learned Rule 3, regarding the “half third tone,” but when I thought about it, I realized it was true and that I even follow it. I guess I unconsciously acquired it.
Anyway, because I found them somewhat hard to find online, I’m going to reproduce the main tone rules here (leaving out the “half third tone” one) and add some examples to flesh them out a bit.
Mandarin Tone Sandhi
When there are two 3rd tones in a row, the first one becomes 2nd tone. Examples: 你好 (nǐ + hǎo = ní hǎo), 很好 (hěn + hǎo = hén hǎo), 好懂 (hǎo + dǒng = háo dǒng).
不 is 4th tone except when followed by another 4th tone, when it becomes second tone. Examples: 不对 (bù + duì = bú duì), 不去 (bù + qù = bú qù), 不错 (bù + cuò = bú cuò).
一 is 1st tone when alone, 2nd tone when followed by a 4th tone, and 4th tone when followed by any other tone. Examples: 一个 (yī + gè = yí gè), 一次 (yī + cì = yí cì), 一半 (yī + bàn = yí bàn), 一般 (yī + bān = yì bān), 一毛 (yī + máo = yì máo), 一会儿 (yī + huǐr = yì huǐr).
Again, it’s important for beginners to memorize these rules because textbooks will often not remind you. They usually provide words’ original tones before tone sandhi.