In Mandarin Chinese there are 21 initial sounds:
What is Initial Sound?
Some Chinese consonants are rather similar to English consonants, but it's important to hear the differences and get all details as accurate as possible! They can be classified into the following categories:
Labial: a sound made with use of one or both your lips. They are: b, p , m, f.
Alveolar: formed with the tip of the tongue against the bony ridge behind the upper front teeth. They are: d, t, n, l.
Velar: formed with the back of the tongue close to or touching the soft part of the roof of the mouth. They are: g, k, h.
Retroflex: formed with the tongue curled back so that it touches (or almost touches) the hard part of the roof of the mouth. They are: zh, ch, sh, r.
Dental sibilant: formed with the tip of the tongue close to or touching the back of the upper front teeth. They are: z, c, s.
Definition for Initial Terminology:
Unaspirated v/s aspirated consonants:
Aspiration means exhalation, a puff of air. In many European languages, the difference between the sounds of "b/p", "d/t" and "g/k" is usually that the first in each pair is voiced (i.e. you can feel you larynx "buzzing" when you pronounce the letters) and the second not voiced (i.e. there is no "buzzing"). In Chinese the difference between these consonant pairs is that the first in each pair is unaspirated (i.e. you exhale very little) and the second is aspirated (i.e. you exhale noticeably).
In Chinese we find the following pairs of the pairs of unaspirated/aspirated consonants: "b/p", "d/t", "g/k", "j/q", "zh/ch", and "z/c". Pay special attention to make the difference clear when pronouncing these letters!
Unvoiced v/s voiced fricatives:
Fricative consonants are produced with articulatory restriction sufficient to produced friction. A voiced fricative should cause your larynx to "buzz" (e.g. the sounds "v" and "z" in English) and an unvoiced fricative will not affect your larynx (e.g. English "f" and "s"). In Mandarin Chinese, the voiced fricatives are "l" and "r", while the unvoiced fricatives are the "blowing" sounds "f", "h", "s", "sh" and "x".