Articulation and Phonology Disorders 25giving vowels their distinctive acoustic qualities. The lower lip and the upper incisors approxi-
mate each other in the production of phonemes such as /v/ and /f/.
The human tongue is the most impor tant articulator and consists of the root, base, and blade.
Intrinsic tongue muscles have their origin and attachment within the tongue. These muscles pri-
marily shape the tongue for speech and mastication (chewing). Extrinsic tongue muscles have their
attachment outside the tongue and are primarily involved in moving it. According to Ladefoged
and Maddieson (1988), there are approximately 16 dif fer ent places of consonant articulation in the
world’s languages.
Phonetics
In the mid-1800s, scientists created the International Phonetic Alphabet (IPA). One reason
was to make the labeling of speech sounds consistent. In En glish, 26 letters can be used for
labeling the 44 phonemes of the language. Obviously, this creates situations in which some
graphemes (letters) must be used for more than one sound and vice versa. Ideally, the speech
sound, the phoneme, should always be represented by one and only one letter. The IPA provides
for that phoneme– grapheme equality. It also specifies the acoustic and perceptual features of
each phoneme. Figure 2-2 shows the IPA grapheme for each phoneme and provides examples of
pronunciation.
Figure 2-2. IPA symbols and examples of pronunciation.
p^ m^
h^ ð^
v^ k^
f^ l^
θ^ g^
ʃ^ z^
n^ ŋ^
t^ b^
d^ dʒ^
s^ j^
w^ ʧ^
r^ ʒ^U^ ɛ^
ɝ^ o^
ɪ^ ^^
ɑ^ ɔ^
æ^ u^
i^ e^