Vocal Tract Physiology

December 2, 2014

Almost There…• The final interim course project report is due today!

• I’ll get your last graded homeworks back to you on Thursday.

• We’ll be doing palatography today…

• But we’ll also have USRI evaluations at the end of class!

• Final exam review session?

• The last mystery spectrogram has been posted!

• On Thursday, we’ll talk about:

• Audition

• Synthetic Speech

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]!

• Lip muscles adjust immediately for the sudden jaw lowering...

• Adjustment happens faster than electrical signals can travel to the motor cortex and back!

Abbs et al. EMG data

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

A Word of Caution• The vowel system of English can vary greatly from one dialect to another.

• Ex: the vowels of Canadian English have shifted away from their American counterparts…

• (for some, but not all, speakers)

• Shift #1:

• Shift #2:

Unshifted:

Unshifted:

• There are also new shifts underway!

• Shift #3: “head”

• Shift #4: “hid”

• Shift #5: “hood”

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.

Electro-palatography

Therapeutic Applications