Some sounds are attributed with certain effects,
such as softness, hardness, smoothness, etc.
From soft to hard:
Continuant（连续音）and nasals（鼻音）:/l/, /r/, /m/, /n/, /ŋ/
Fricatives（摩擦音）and aspirants（气音）: /v/, /f/, /s/, /z/, /θ/, /ð/
Affricates（塞擦音）: /tʃ/, /dʒ/
Plosives（爆破音）: /p/, /b/, /k/, /g/, /t/, /d/