23. Additional Tone Sandhi Rules

Tone sandhi rules for yī (one)

The word (one) bears a 1st tone when it is pronounced alone or at the end of an utterance.

Character and PinyinEnglish Equivalent
unify
monotonous

It is produced with the 4th tone () when it is followed by the 1st, 2nd or 3rd tone.  For example:

Pinyin vs. PronunciationEnglish Equivalent
yī + tiān → yì tiān
one day
yī + tóng → yì tóng
together
yī + qǐ → yì qǐ
together

When is followed by any syllable bearing a 4th tone, it is produced with a rising tone, with a pitch contour identical to that of the 2nd tone ().  For example:

Pinyin vs. PronunciationEnglish Equivalent
yī + miàn → yí miàn
at the same time
yī + jiàn → yí jiàn
one piece of
yī + gè → yí gè
one unit of
yī + kuài → yí kuài
one piece of

Listening Quiz

Tone sandhi rules for bù (not)

(not) also changes its tone depending on the tone of the following syllable.  When it is standing alone, or being followed by a 1st , 2nd or a 3rd tone syllable, it is pronounced with the 4th tone ().  For example:

Pinyin vs. PronunciationEnglish Equivalent
bù + chī → bù chī
do not eat
bù + máng → bù máng
not busy
bù + hăo → bù hăo
not good

When it is followed by a 4th tone syllable, it is pronounced with a 2nd tone ().  For example:

Pinyin vs. PronunciationEnglish Equivalent
bù + shì → bú shì
is not
bù + duì → bú duì
not correct
bù + cuò → bú cuò
not bad

Listening Quiz