point, whereby Deaf Persons do discern a _Voice_ from a _Mute
Breath_, is a great Mystery of Art; and if I may have leave to say so,
it is the _Hearing of Deaf Persons_, or at least equivolent thereunto,
_viz._ that trembling Motion and Titillation, which they perceive in
their own _Throat_, whilst they of their own accord do give forth a
_Voice_; that therefore the Deaf may know, that I open my Mouth _to
emitt a Voice_; not simply to yawn, or to draw forth a _Mute Breath_,
I put their Hand to my _Throat_ that they may be made sensible of that
tremulous Motion, when I utter my _Voice;_ then I put the same Hand of
theirs to their own _Throat_, and command them to imitate me; nor am I
discouraged, if at the beginning their _Voice_ is harsh and difficult;
for in time it becomes more and more polite.

If I gain their _Voice_, which for the most part I do at the first
time, I soon learn them to pronounce _Vowels_, _viz._ I bid them so to
moderate the _opening of their Mouth_, whilst they do form a _Voice_
in their _Throat_, as I have said above, concerning the Formation of
the _Vowels_; but that they may do that the more easily, I hold a
_Looking-Glass_ to them, because they cannot from Sight alone imitate
those diverse Motions of the _Jaws_, of the _Tongue_, and of the
_Lips_, unless they had oftentimes tried it before a Looking-Glass.
Thence I learned, that that common belief, (that so soon as Hearing is
restored to Deaf Persons, they will speak) to be false, for it seems
not to me, that there is so great a consent betwixt the Organs of
_Voice_, and of Hearing, that at the first blush they can imitate a
_Voice_ that is heard; but by often imitating a _Voice_ or _Breath_
received from another, and also by hearing their own at the same time,
we find at length a likeness between both, and after this manner we
all learn to speak; for he who learns to speak, it is all one, as if
he did learn some other Art; for by a long accustoming, the Organs are
rendered apt and pliable: Hence it is, that sometimes we come not to
pronounce aright Foreign Letters but after a long time. Now, it would
be well observed or considered, that I presently prescribe all the
Letters to Deaf Persons, or else they could not fix in their Minds
their _Idea's_ of them, and I seldom teach more than two or three
Letters in one day, least the _Idea's_ be confounded; but I bid them
very often to repeat them, and to write them down as they are
pronounced by me.