Neutral tones

A fifth tone exists that you can’t exactly count among the four basic tones because

it’s actually toneless, or neutral. You never see a tone mark over a fifth tone, and

you say it only when you attach it to grammatical particles or the second character

of repetitive syllables, such as bàba 爸爸 (bah-bah) (father) or māma 妈妈 (媽媽)

(mah-mah) (mother).

Tonal changes in yī and bù

Just when you think you’re getting a handle on all the possible tones and tone

changes in Chinese, I have one more aspect to report: The words yī 一 (ee) (one)

and bù 不 (boo) (not or no) are truly unusual in Chinese, in that their tones may

change automatically depending on what comes after them. You pronounce yī by

itself with the first tone. However, when a first, second, or third tone follows it, yī

instantly turns into a fourth tone, such as in yì zhāng zhǐ 一张纸 (一張紙) (ee jahng

jir) (a piece of paper). If a fourth tone follows yī, however, it automatically becomes

a second tone, such as in the word yíyàng 一样 (一樣) (ee-yahng) (the same).