Transcript Vocal Tract Musculature

Vocal Tract Physiology
April 5, 2013
The Toolkit
•
There are four primary active articulators in speech.
•
(articulators we can move around )
1. The lips
2. The lower jaw (mandible)
3. The tongue
4. The velum
•
The pharynx can also be constricted, to some extent.
•
Separate sets of muscles control each articulator...
Articulatory Speed
• The gold medal goes to the tongue tip...
• which is capable of 7.2 - 9.6 movements per
second.
• The rest:
• Mandible
5.9 - 8.4 movements per second
• Back of tongue 5.4 - 8.9
• Velum
5.2 - 7.8
• Lips
5.7 - 7.7
• Note: lips can be raised and lowered faster than they
can be protruded and rounded.
1. The Lips
• The orbicularis oris
muscle surrounds the lips.
• Contraction compresses
and rounds the lips.
• A muscle called the
mentalis also protrudes
the lips.
• Contraction of the
risorius muscle retracts
the corners of the lips...
• and spreads them.
By the way...
• The vowel [i] is typically produced with active lip
spreading.
• “Say cheese!”
• What acoustic effect would this have?
• Lips Normal:
• Lips Spread:
• Check ‘em out in Praat.
2. The Jaw
• Several different muscles are used to both lower and
raise the mandible.
• Primary raisers:
• Masseter
• Temporalis
• Internal
pterygoid
2. The Jaw
• Several different muscles are used to both lower and
raise the mandible.
• Lowerers:
• Anterior belly
digastricus
• Geniohyoid
• Mylohyoid
• Note: in lowering, the mandible also retracts.
Articulatory Control
• People can produce vowels perfectly fine even when
a bite block holds their jaws open. (Lindblom, 1979)
• Adults get the formants right, right from the start...
• But kids need a little time to adjust.
• Abbs et al. (1984) experimented with pulling down
people’s jaws...
• when they had to say sequences like [aba] and
[afa]!
Abbs et al. EMG data
• Lip muscles
adjust
immediately for
the sudden jaw
lowering...
• Adjustment
happens faster
than electrical
signals can
travel to the
motor cortex
and back!
3. The Tongue
•
The muscles controlling the tongue consist of:
1. Intrinsic muscles
•
(completely within the tongue)
2. Extrinsic muscles
•
•
(connect the tongue to outside structures)
The intrinsic muscles include:
1. The superior longitudinal muscle
2. The inferior longitudinal muscle
3. Transverse muscles
4. Vertical muscles
Tongue: Sagittal View
• The superior
longitudinal muscle
pulls the tongue tip up
and back.
• Instrumental in
producing alveolars
and retroflexes.
• The inferior
longitudinal muscle
pulls the tongue tip
down and back.
• Helps with tongue
blade articulations.
Tongue: Coronal View
• The transverse muscles pulls in the edges of the
tongue, and also lengthens the tongue to some extent.
• Helpful in producing laterals.
• Contraction of the vertical muscles flattens the tongue.
• Interdentals?
Extrinsic #1: Genioglossus
• The genioglossus
connects the tongue to
both the mandible and the
hyoid.
• Contraction of the
posterior genioglossus
moves the whole tongue
up and forwards.
• Crucial in palatals.
• Contraction of the
anterior genioglossus
curls the tongue tip down
and back.
Gene-ioglossus
Gene Simmons, of the rock band KISS, is
famous for his use of the genioglossus muscle.
Extrinsic #2: Styloglossus
• The styloglossus
connects the tongue to the
“styloid process” in front of
the ear.
• Pulls the tongue up and
back.
• ...for velar articulations.
• May also help groove
(sulcalize) the tongue.
Extrinsic #3: Hyoglossus
• The hyoglossus
connects the tongue to the
hyoid bone.
• Pulls the tongue down
and back.
• = pharyngeals
• Can also pull the sides of
the tongue down.
Extrinsic #4: Palatoglossus
• The palatoglossus connects
the tongue to the soft palate.
• Can be used to raise the back
of the tongue.
• And also to lower the
velum!
• Lowering the back of the
tongue may inadvertently pull
the velum down...
• leading to passive
nasalization of low vowels.
• Note: Great Lakes vowel shift
Chain Shifting
• The Great Lakes Shift is called a chain shift, because
first one vowel moves...
• And then a series of others follow.
• In this case, the first shift was:
• Theory: vowels have to stay distinct from one another.
• So listeners can understand what’s being said.
Back to the Shift
• The Great Lakes Shift was first noticed in the 1960s.
The Shift, Diagrammed
4. Velar Muscles
• The levator palatini
raises the velum.
• (connects the velum to
the temporal bone)
• The velum is lowered by
both the palatoglossus and
the palatopharyngeus...
• which connects the
palate to the pharynx.