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Intelligibility of Speech

Speech/language pathologists work with clients who have an inability to produce speech sounds accurately.

Some of the factors taken into consideration when listening or evaluating intelligible speech include:

• Does the child come close to correct production (distortion) or does he/she completely omit the sound (i.e., hat – ha-).
• If he/she substitutes one sound for another (i.e., wed – red), is it a typical substitution for this age or is it an unusual substitution that confuses the listener?
• Do the errors render speech less intelligible (or more immature) than it should be?

A general guideline for measuring intelligibility is as follows:

• 2-2-1/2 years – 50% intelligible to strangers, 80% intelligible to parents
• 3-1/2 years – 80 % intelligible to strangers, 95% intelligible to parents
• 4-1/2 years – 100% intelligible to strangers, 100% intelligible to parents
• Smooth blending of sound develops continuously through the ages of 4 – 7

The overall goal of speech therapy is to increase basic intelligibility. The clinician may work on one age-appropriate sound or group of sounds at one time. Treatment is individualized and determined upon initiation of therapy.