The phonological system of the modern standard language in Chinese, Putonghua or Guoyu, can be represented by letters. Of all the letters of English alphabet, 25 letters are used for Pinyin. Letter 'v' is not used, while letter 'ü' is added to represent the vowel sound 'yu'.

Consonant letters

    There are 20 consonant letters use in Putonghua. Letter 'V' is not used. Three consonants are represented by combinations of two letters - 'zh', 'ch' and 'sh':
 

Note:

• The actual sound you hear for each letter is a combination of the consonant and a vowel.
• 'y' and 'w' are used for 'i' and 'u' respectively if they appear at the beginning of a syllable: e.g. 'ya [ia]'  'wa [ua]'. Or they are added when 'i' and 'u' are independent syllables, e.g. 'yi [i]', 'wu [u]'

Vowel letters

    There are 6 vowel letters used in Putonghua:
 

Tones

    There are four tones in Putonghua: the 1st tone, the 2nd tone, the 3rd tone and the 4th tone. They are superimposed over the main vowel of a syllable and represented by diacritic markers.
 

1st ton: high and long	2nd tone: rising and long
3rd tone: low and short	4th tone: falling and short

Syllables

    Syllables are composed by consonants, vowels and tone. According to the trational notation, a syllable is composed by a 'initial' and a 'final'. An initial is the first sound of a syllable, usually, a consonant. A final is the rest part of the syllable. The final can be a single vowel, or a combination of vowels, or combination of vowels and nasals 'n' or 'ng': For example: (the following syllables are not human voice, they are produced by Bell-lab automatic speech synthecizing program)
 

For more detailed introduction to Chinese pronunciation and Romanization click here.

For more resources on Chinese pronunciation click here.