The following diphthongs are in common use, viz.:  oi, oy, ou, ow, ae, ai, au, aw, ay, ea, ei, eo, eu, ew, ey, ia, ie, oa, oe, ua, ue, ui; as in toil, boy, round, plow, seal, coal, head, sail, say, aught, yeoman.  Of these, oi, oy, ou, and ow are generally proper diphthongs; though sometimes ou and ow are improper, as in famous, where o is silent, and in slow, where w is silent.

A Triphthong is the union of three vowels in one syllable; as, eau in beau, iew in view.  The triphthong is properly a union of letters, not sounds.

OF THE VARIOUS SOUNDS.

All the vowels, and some of the consonants, have several sounds; in this book these sounds are indicated by diacritical marks, as in the following tables: 

Table of vocals. 
Long Sounds.

Sound  as is
-----  -----
a      ate
a      care
a      arm
a      last
a      all
oo     fool

e      eve
e      err
i      ice
o      ode
u      use

Short Sounds.

Sound  as is
-----  -----
a      am
e      elm
i      in
o      odd
u      up
oo     look

Diphthongs.

oi,oy,as in oil, boy ou,ow, as in out, owl

Table of SUBVOCALS
Sound  as is
-----  -----
b      bib
d      did
g      gig
j      jug
n      nine
m      maim
ng     hang
l      lull

v      valve
th     this
z      zinc
zh     azure
r      rare
w      we
y      yet

Table of aspirates
Sound  as is
-----  -----
f      fife
h      him
k      cake
p      pipe
s      same

t      tart
sh     she
ch     chat
th     thick
wh     why

Note.—­The foregoing forty-four sounds are those most employed in the English language.  Some of these sounds are represented by other letters, as shown in the following table.  For further instruction concerning the sounds, see Lessons 36-57.

Table of substitutes. 
Sound  for  as in
-----  ---  -----
a      o    what
e      a    there
e      a    feint
i      e    police
i      e    sir
o      u    son
o      oo   to
o      oo   wolf
o      a    fork
o      e    work
u      oo   full
u      e    burn
u      oo   rude
y      i    fly

y      i    myth
c      k    can
c      s    cite
ch     sh   chaise
ch     k    chaos
g      j    gem
n      ng   ink
s      z    as
s      sh   sure
x      gz   exact
gh     f    laugh
ph     f    phlox
qu     k    pique[1]
qu     kw   quit

[Footnote 1:  The u is canceled in this book when qu is sounded like k.]

W, in its vowel sounds, corresponds with u; an in new (pro. nu).

A has, in a few words, the sound of e; as in any (pro. en’ny).

U has, in a few words, the sound of e; as in bury (pro. ber’ry); or that of i, as in busy (pro. biz’y).

OF THE CONSONANTS.