[…] the narrowing of the organs may be pushed even to the point of complete closure, the element of form, of oral modification, coming thus to prevail completely over that of material, of tone: the product, in that case, is made distinctly audible only as the contact is broken; and we call it a mute.
- Whitney (1875), a pag.61

A mute […] is hardly audible as final, unless the contact is broken again with a puff of ‘flatus’; and something of the same disability clings also to the other consonants.
- Whitney (1875), a pag.72

We have seen that in the classes of mutes and fricatives the sounds go in pairs, one produced by mere breath, the other by intonated breath, forced through the same position of the organs […]
- Whitney (1875), a pag.66