Why?

Why invent such a language?
I was inspired by the words spelled uhuh and uh-uh and mean 'yes' and 'no' respectively. So I thought how would a language made up of solely nasal sounds be? And ‘Mhmmz is my answer to that question.

Why would people speak such a language?
I imagine it spoken by a sect, that wants to rid themselves of all opinion. They gave up speaking, because that way they avoid anyone quoting them for having an opinion. Some of the extremists even sew their mouths shut, leaving only enough room for a straw of bamboo, through which they could eat mashed foods.

But they couldn't keep it up, so eventually they started communicating in this language. Although if you asked them, they would deny that it is language (I'm going to make ‘Mhmmz mean 'non-language'). (And, yes, denying that what they speak is language, is opinion: I didn't say that they didn't have opinion, that's just their ideal, but most of them can't live up to it)