M:is tooth?
mouth:嘴，口。
m是牙齿。u是张开的嘴，th指的是人。
mouth =muth.
M:tooth .
u:splay .
th:indicate a man .

Question

M:is tooth?
mouth:嘴，口。
m是牙齿。u是张开的嘴，th指的是人。
mouth =muth.
M:tooth .
u:splay .
th:indicate a man .

Answer

'th' indicates a quality! Width 口

Answer

M is not a tooth.  The 'mmm' sound is unrelated to teeth, and used to be an icon for water.  A  closed-lips sound doesn't signify teeth.

The 'tooth' pictograph looks like a rotated M: Σ which is the Greek sigma, or before that the "sh=šin" (I love hačeks). So "S" actually is "teeth".

Could you post the url link where you are getting all this from?  I tried to search for it, but couldn't find it.