The Barnett–Chao system of romanization for writing Cantonese is based on the principles of the Gwoyeu Romatzyh

Gwoyeu Romatzyh

Gwoyeu Romatzyh , abbreviated GR, is a system for writing Mandarin Chinese in the Latin alphabet. The system was conceived by Y.R. Chao and developed by a group of linguists including Chao and Lin Yutang from 1925 to 1926. Chao himself later published influential works in linguistics using GR...

 system (abbreviated as GR) for writing Mandarin Chinese in the Latin alphabet. The Barnett–Chao system has had a limited following and appears almost exclusively in Y.R. Chao

Yuen Ren Chao

Chao Yuen Ren was a Chinese American linguist and amateur composer. He made important contributions to the modern study of Chinese phonology and grammar....

's Cantonese Primer. The two reasons for its lack of widespread adoption despite the inherent benefits of tonal spelling are that it 1) requires a large number of roman letters to represent each toned syllable, and 2) like GR, it uses a complex system for representing tone that makes the system difficult to learn and obscures the basic relationship between spelling and tone.

Description

Like GR spelling, B–C spelling uses contrasting unvoiced/voiced pairs of consonants to represent aspirated and unaspirated sounds. B–C also uses single versus double vowels letters to represent certain short + high versus long + low final vowels even in open syllables where the contrast does not exist: buk, buut, baa, and different letters to represent the contrast in other cases: sek, sin. Some vowels are only long and do not use doubling to represent length: ea, o, y.

The Cantonese high and low pitch registers are indicated by inserting -h- or -r- between the initial and final: bhat, brat. Medium pitch register has no insert, and is considered the basic form: baa.

Basic forms

The following two tables list the B–C spellings of initials and finals with their corresponding IPA values.

Initials

b [p]	p [pʰ]	m [m]	f [f]
d [t]	t [tʰ]	n [n]	l [l]
g [k]	k [kʰ]	ng [ŋ]	x [h]
q [ʔ]
z [ts]	c [tsʰ]	s [s]
gw [kw]	kw [kʰw]	j [j]	w [w]

Finals

aa [a]	aai [ai]	aau [au]	aam [am]	aan [an]	aang [aŋ]	aap [ap]	aat [at]	aak [ak]
	ai [ɐi]	au [ɐu]	am [ɐm]	an [ɐn]	ang [ɐŋ]	ap [ɐp]	at [ɐt]	ak [ɐk]
ea [ɛ]	ei [ei]				eang [ɛŋ]			eak [ɛk]
i [i]		iu [iu]	im [im]	in [in]	eng [ɪŋ]	ip [ip]	it [it]	ek [ɪk]
o [ɔ]	oi [ɔi]	ou [ou]		on [ɔn]	ong [ɔŋ]		ot [ɔt]	ok [ɔk]
uu [u]	uui [ui]			uun [un]	ung [ʊŋ]		uut [ut]	uk [ʊk]
eo [œ]		eoi [ɵy]		eon [ɵn]	eong [œŋ]		eot [ɵt]	eok [œk]
y [y]				yn [yn]			yt [yt]
			m [m̩]		ng [ŋ̩]

• The finals m and ng can only be used as standalone nasal syllables.

Tones

There are nine normal tones in six distinct tone contour

Tone contour

A tone contour is a tone in a tonal language which shifts from one pitch to another over the course of the syllable or word. Tone contours are especially common in East and Southeast Asia, but occur elsewhere, such as the Kru languages of Liberia and the Ju languages of Namibia.-Themes:When the...

s and two modified tones in Cantonese.

B–C spelling represents the normal tones using the letters h and r before and after the main vowel of the final as well as spelling changes of certain finals as described below.

Before the vowel of the final, h indicates that the start of the tone is high; after the vowel of the final, h indicates that the tone falls, however a falling contour is also indicated by a change in spelling in some finals: Vi > Vy, Vu > Vw, ng > nq, n > nn, m > mm for example saan "disperse" and shaann "mountain", sou "number" and show "whiskers", sai "small" and shay "west".

Before the vowel of the final, r indicates that the start of the tone is low; after the vowel of the final, r indicates that the tone rises, however a rising contour is also indicated by a change in spelling in some finals: Vi > Ve, Vu > Vo for example sai "small" and sae "wash", sou "number" and soo "count".

The modified tones representing high-flat (高平) and modified mid-rising (高升) when the original tone is not mid-rising are indicated by adding an x or v after the end of the syllable. High-register syllables that end in a stop (entering tone) are already considered high-flat and cannot take x.

No.	Description	B–C examples
1	high-falling	shih	shinn
2	mid-rising	sir	sirn
3	mid-flat	si	sin
4	low-falling	srih	srinn
5	low-rising	srir	srirn
6	low-flat	sri	srin
7	high-entering			shek
8	mid-entering			sit
9	low-entering			srek
10	high-flat	shihx	shinnx
11	mid-rising modified	shihv	shinnv

Examples

Traditional Traditional Chinese character Traditional Chinese characters refers to Chinese characters in any character set which does not contain newly created characters or character substitutions performed after 1946. It most commonly refers to characters in the standardized character sets of Taiwan, of Hong Kong, or in the Kangxi...	Simplified Simplified Chinese character Simplified Chinese characters are standardized Chinese characters prescribed in the Xiandai Hanyu Tongyong Zibiao for use in Mainland China. Along with traditional Chinese characters, it is one of many standard character sets of the contemporary Chinese written language...	Yale Romanization with Tone Marks	Barnett–Chao Romanization
		gwóng jàu wá	Gworngzhawwraav
		yuht yúh	jrytjryr
		néih hóu	nree xoo