broad system to represent the phoneme written in the narrow system. The difference between and , or and , etc. is similarly a difference in aspiration and not in voicing. One particular aspect of the S. L. Wong system is the differentiation of the fricative and affricative initials into ( ) and ( ) respectively to reflect the difference in Putonghua between (/x/ /q/ /j/) and (/s/ /c/ /z/), even though it was acknowledged that ( ) are "duplicates" of ( ) and are pronounced exactly the same in modern Cantonese. Single articulation Coarticulation Affricates Summary In Cantonese, in scheme is the allophone of , and in IPA; is the allophone of , and ; is the allophone of , and . Wong noted the [ts2], [dz2], [s2] are allophones to , , in Cantonese and made distinctions for comparative purpose only. They are not used for transcription. For aspiration, in the scheme is for in IPA and for ; for and for ; for and for ; for and for ; for , and and for , and . For labialisation, is for and for . Tones There are basically six tones in Cantonese. Tones play an important role in distinguishing meanings. Tones also form melodies in poem and prose composition. In classical Chinese, four basic tones are the level (平 ˌp‘iŋ), the rising (上 ˏsœŋ), the going (去 ˉhœy) and the entering (入 ˍjɐp). The entering tone is a special case for when a syllable ends with [p], [t], or [k]; those syllables have a shorter quality than others. The tones are further divided into upper and lower level, i.e. the rising and going tones. The entering tone is divided into upper entering, middle entering and lower entering. The upper entering is the same tone as upper level, middle entering the same as upper going, and lower entering the same as lower going. There are two ways to mark tones in the scheme, appending a number to the end of the syllable or using diacritical marks. Each tone's corresponding contour based on Yuen Ren Chao scheme in later studies is given in the second line of its table entry. While the system uses 1 to 9 as tone numbers, some adaptations use a 1 to 6 system, i.e. replacing redundant 7, 8, 9 with 1, 3, 6 respectively. Some dictionaries use slightly different tone symbols. For example, in