Interdental lisping is when the tongue protrudes between the front teeth when producing /s/ or /z/, resulting in a “th” sound.  The /s/ becomes a voiceless “th”, as in “think”, and the /z/ becomes a voiced “th”, as in “those”.  Interdental lisping, also be known as “frontal lisping”, is a normal developmental phase that some children go through.  Because of this, if a person continues this pattern of speech past the age when most have outgrown it (around 4 ½ years old), his speech may be perceived as juvenile. 

 
What about other interdental sounds?

Other sounds may be produced with a protruding tongue as well.  Most commonly, lingual protrusion during the “sh”, “zh” (as in “equation”), “ch” and “j” sounds may accompany the interdental lisping of /s/ and /z/. 

In addition, lingual alveolar sounds (i.e., /t/, /d/, /n/, /l/) that should be produced with the tongue on the alveolar ridge may be produced with the tongue protruding between the front teeth.

What can I do to work on interdentalized /s/ and /z/? 

1.   Establish auditory discrimination

2.   Provide focused auditory input.

3.   Get correct production of /s/ in isolation.

4.   Move through the hierarchy of production levels (syllables, words, phrases/sentences, reading activities, and conversational speech) with the sound in each position.  Note:  For lisping, I prefer to start with /s/ in the initial position.

Want to know more?

Detailed instructions for working on interdentalized /s/ and /z/, printable materials, and activity ideas are coming soon in the June email.  Make sure you get yours!  Enter and activate your email address here before the end of the month and receive: 

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