Origins

The Commission on the Unification of Pronunciation, led by Wu Zhihui from 1912 to 1913, created a system called Zhuyin Zimu,^[2] which was based on Zhang Binglin's shorthand. It was used as the official phonetic script to annotate the sounds of the characters in accordance with the pronunciation system called "Old National Pronunciation" (Laoguoyin).^[5] A draft was released on July 11, 1913, by the Republic of China National Ministry of Education, but it was not officially proclaimed until November 23, 1928.^[2] It was later renamed first Guoyin Zimu and then, in April 1930, Zhuyin Fuhao. The last renaming addressed fears that the alphabetic system might independently replace Chinese characters.^[6]

Modern use

A guide on how to typeset Bopomofo alongside characters. (1936, Li Jinxi)

Bopomofo is the predominant phonetic system in teaching, reading and writing in elementary school in Taiwan. In elementary school, particularly in the lower years, Chinese characters in textbooks are often annotated with Bopomofo as ruby characters as an aid to learning. Additionally, one children's newspaper in Taiwan, the Mandarin Daily News, annotates all articles with Bopomofo ruby characters.

It is also the most popular way for Taiwanese to enter Chinese characters into computers and smartphones and to look up characters in a dictionary.

In teaching Mandarin, Taiwan institutions and some overseas communities such as Filipino Chinese use Bopomofo.

Bopomofo is shown in a secondary position to Hanyu Pinyin in all editions of Xiandai Hanyu Cidian from the 1960 edition to the current 2016 edition (7th edition).

Bopomofo is also used to transcribe other Chinese dialects, most commonly Taiwanese Hokkien and Cantonese, however its use can be applied to practically any dialect in handwriting (because not all letters are encoded). Outside of Chinese, Bopomofo letters are also used in Hmu and Ge languages by a small number of Hmu Christians.^[7]

Stroke order

Bopomofo is written in the same stroke order rule as Chinese characters. ㄖ is written with three strokes, unlike the character from which it is derived (Chinese: 日; pinyin: rì), which has four strokes.

ㄧ can be written as a vertical line () or a horizontal line (); both are accepted forms. Traditionally, it should be written as a horizontal line in vertical writing, and a vertical line in horizontal writing. The People's Republic of China almost exclusively uses horizontal writing, so the vertical form (in the rare occasion that Bopomofo is used) has become the standard form there. Language education in the Republic of China generally uses vertical writing, so most people learn it as a horizontal line, and use a horizontal form even in horizontal writing. In 2008, the Taiwanese Ministry of Education decided that the primary form should always be the horizontal form, but that the vertical form is accepted alternative.^[16] Unicode 8.0.0 published an errata in 2014 that updates the representative glyph to be the horizontal form.^[17] Computer fonts may only display one form or the other, or may be able to display both if the font is aware of changes needed for vertical writing.

Tonal marks

As shown in the following table, tone marks for the second, third, and fourth tones are shared between bopomofo and pinyin. In bopomofo, the mark for first tone is usually omitted but can be included,^[18][19] while a dot above indicates the fifth tone (also known as the neutral tone). In pinyin, a macron (overbar) indicates the first tone, and the lack of a marker usually indicates the fifth (light) tone.

Unlike Hanyu Pinyin, Bopomofo aligns well with the Chinese characters in books whose texts are printed vertically, making Bopomofo better suited for annotating the pronunciation of vertically oriented Chinese text.

When used in conjunction with Chinese characters, Bopomofo is typically placed to the right of the Chinese character vertically in both vertical print^[22][23] and horizontal print^[24] or to the top of the Chinese character in a horizontal print (see Ruby characters).

Example

Below is an example for the word "bottle" (pinyin: píngzi):

Erhua transcription

Words rhotacized as a result of erhua are spelled with ㄦ attached to the syllable (like 歌兒（ㄍㄜㄦ） gēr). In case the syllable uses other tones than the 1st tone, the tone mark is attached to the penultimate letter standing for syllable nucleus, but not to ㄦ (e.g. 哪兒（ㄋㄚˇㄦ） nǎr; 一（ㄧ）點兒（ㄉㄧㄢˇㄦ） yīdiǎnr; 好（ㄏㄠˇ）玩兒（ㄨㄢˊㄦ） hǎowánr).^[25]

Pinyin

Bopomofo and pinyin are based on the same Mandarin pronunciations; hence there is a one-to-one correspondence between the two systems:

¹ Not written.

² ⟨ü⟩ is written as ⟨u⟩ after ⟨j⟩, ⟨q⟩, ⟨x⟩, or ⟨y⟩.

³ ⟨ㄨㄛ⟩/⟨-uo⟩ is written as ⟨ㄛ⟩/⟨-o⟩ after ⟨ㄅ⟩/⟨b-⟩, ⟨ㄆ⟩/⟨p-⟩, ⟨ㄇ⟩/⟨m-⟩, ⟨ㄈ⟩/⟨f-⟩.

⁴ ⟨weng⟩ is pronounced [ʊŋ] (written as ⟨-ong⟩) when it follows an initial.

Chart

Taiwanese Hokkien

In Taiwan, Bopomofo is used to teach Taiwanese Hokkien, and is also used to transcribe it phonetically in contexts such as on storefront signs, karaoke lyrics, and film subtitles.

Three letters no longer used for Mandarin are carried over from the 1913 standard:

23 more letters were added specifically for Taiwanese Hokkien:

Two tone marks were added for the additional tones: ˪, ˫

Cantonese

The following letters are used in Cantonese.^[26]

If a syllable ends with a consonant other than -an or -aan, the consonant's letter is added, then followed by a final middle dot.

-ㄞ is used for [aːi] (aai) (e.g. 敗, ㄅㄞ baai6, "to be defeated").

-ㄣ is used for [ɐn] (an) (e.g. 跟, ㄍㄣ gan1, "to follow"), and -ㄢ is used for [aːn] (aan) (e.g. 間, ㄍㄢ gaan1, "within"). Other vowels that end with -n use -ㄋ· for the final ㄋ. (e.g. 見, ㄍㄧㄋ· gin3, "to see").

-ㄡ is used for [ɐu] (au). (e.g. 牛, ㄫㄡ, ngau4, "cow") To transcribe [ou] (ou), it is written as ㄛㄨ (e.g. 路, ㄌㄛㄨ lou6, "path").

ㄫ is used for both initial ng- (as in 牛, ㄫㄡ, ngau4) and final -ng (as in 用, ㄧㄛㄫ·, jung⁶ "to use").

ㄐ is used for [t͡s] (z) (e.g. 煑, ㄐㄩ zyu2, "to cook") and ㄑ is used for [t͡sʰ] (c) (e.g. 全, ㄑㄩㄋ· cyun4, "whole").

During the time when Bopomofo was proposed for Cantonese, tones were not marked.

Input method

An example of a Bopomofo keypad for Taiwan

A typical keyboard layout for Bopomofo on computers

Bopomofo can be used as an input method for Chinese characters. It is one of the few input methods that can be found on most modern personal computers without having to download or install any additional software. It is also one of the few input methods that can be used for inputting Chinese characters on certain cell phones.. On the QWERTY keyboard, the symbols are ordered column-wise top-down (e.g. 1+Q+A+Z)

Unicode

Bopomofo was added to the Unicode Standard in October 1991 with the release of version 1.0.

The Unicode block for Bopomofo is U+3100–U+312F:

Additional characters were added in September 1999 with the release of version 3.0.

The Unicode block for these additional characters, called Bopomofo Extended, is U+31A0–U+31BF:

Unicode 3.0 also added the characters U+02EA ˪ MODIFIER LETTER YIN DEPARTING TONE MARK and U+02EB ˫ MODIFIER LETTER YANG DEPARTING TONE MARK, in the Spacing Modifier Letters block. These two characters are now (since Unicode 6.0) classified as Bopomofo characters.^[27]