Voice Resonance Week 9: Voice/Resonance and Airflow

What is resonance for speech?

The modification of the phonated sound based on the size and shape of the resonating cavities of the vocal tract; provides the quality and uniqueness of the voice.

What determines resonance for speech?

• The function of the velopharyngeal valve to direct sound in the appropriate cavity

• Size and shape of the resonating cavities (pharyngeal, oral, nasal) 

What is a resonant disorder? 

Abnormal transmission of sound energy through the oral, nasal, and/or pharyngeal cavities of the vocal tract during speech production. 

What are the different resonance disorders? 

• Hypernasality 

• Hyponasality/densaality 

• Cul-de-sac resonance 

• Mixed resonance 

What is hypernasality?

Too much sound in the nasal cavity during the production of oral sounds.

When is hypernasality most perceptible?

On vowels/resonance sounds; voice plosives become nasalized (b to m, d to n).

What does hypernasality do to volume? 

Causes low volume due to the reduction of sound through the oral cavity and absorption of sound in the pharyngeal and nasal cavities. 

What are obligatory distortions? 

Function/articulation placement is normal, and speech distortion is due to an abnormal structure only. 

What is the treatment for obligatory distortions?

Correct the structure, no need for speech therapy

Examples of obligatory distortions:

• Hypernasality due to velopharyngeal insufficiency

• Nasalized voiced consonants (m/b, n/d)

What are compensatory errors? 

Function/articulation placement is abnormal due to an abnormal structure.

What is the treatment for compensatory errors?

Correct the structure and then speech therapy to correct function.

Examples of compensatory errors:

• Substitution of /n? or pharyngeal fricative for oral sounds to compensate for inadequate oral airflow due to a leak in the velopharyngeal valve.

What is cause #1 of hypernasality? 

A velopharyngeal opening: too much air is going through the nasal cavity (increased nasal energy). 

What is cause #2 of hypernasality? 

A thin velum due to a submucous cleft 

What is cause #3 of hypernasality?

Nasal articulation on specific oral sounds due to mislearning.

What is hyponasality?

A reduction in normal nasal resonance during speech, particularly on nasal sounds (individual sounds stuffed up); too little air is coming through the nose. 

What is hyponasality rare for someone with a cleft?

A cleft is when there is an opening, hypo is when there is a blockage (decreased nasal energy, making speech oral). 

What is denasality?

No nasal resonance during speech

What do hyponasality and denasality do to speech sounds?

Nasal consonants sound similar to their oral cognates (b/m, d/n)

What are the causes of hyponasality and denasality?

• Caused by blockage in the nasopharynx or nasal cavity due to:

  • Common cold

  • Shallow pharynx

  • Adenoid hypertrophy

  • Allergies

What is cul-de-sac resonance? 

Sound energy is blocked at the exit of the cavity (muffled resonance). 

How does cul-de-sac resonance occur?

The sound is absorbed by soft tissues because of the blockage in the vocal tract, causing muffled speech and low volume.

What is mixed resonance?

Any combination of hypernasality, hyponasality, and cul-de-sac resonance.

Can hyper and hyponasality occur simultaneously?

No, but they can occur on different sounds in the same speaker.

What are causes of mixed resonance?

VPI and Obstruction, Apraxia

What is nasal emission? 

Escape of airflow through the nose during speech due to a leak in the system; can occur with or without hypernasality  

When is nasal emission audible?

On pressure-sensitive sounds - plosives, fricatives, affricates 

Most audible on voiceless sounds 

What are the types of nasal emission?

1. Nasal Rustle 

2. Audible Nasal Emission 

3. Inaudible Nasal Emission 

4. Phonemic-Specific Nasal Emission 

Nasal Rustle 

Small VP opening 

Audible Nasal Emission

Medium-sized VP opening 

Inaudible Nasal Emission

Large VP opening

Phoneme-Specific Nasal Emission 

Pharyngeal articulation on specific fricative sounds due to compensatory articulation of VP mislearning without VP insufficiency. 

What does perception of nasal emission depend on?

The size of the opening and pressure:

• Small opening results in relatively high velocity/pressure

• Large opening results in relatively low velocity/pressure

1. Secondary Characteristics of Nasal Emission 

Weak or omitted consonants due to inadequate oral airflow 

2. Secondary Characteristics of Nasal Emission 

Short utterance length because leak causes need to take frequent breaths

3. Secondary Characteristics of Nasal Emission 

Nasal grimace due to effort in closing the VP valve

4. Secondary Characteristics of Nasal Emission 

Compensatory articulation productions to increase intelligibility of weak or omitted sounds