“Speech” can be thought of as verbal communication. It is the set of sounds that we make (using our voice and our articulators) that comprise syllables, words, and sentences. Speech alone carries no meaning, it is merely sound. Most speech sounds are mastered by 8-9 years old, with different sounds emerging at different ages.
/s/ and /z/ speech sounds can be challenging for many children. This sound is typically mastered close to 5 years old, however some children may continue to struggle past that point. When producing /s/ and /z/, there are 3 main factors to consider: place, manner, and voicing.
Place of Production:
When producing /s/ and /z/ sounds, most people can be categorized as “tippers” or “dippers.” Tippers will bring their tongue tip up to touch their alveolar ridge (the ridge behind our top teeth), whereas dippers will bring their tongue tip down towards their bottom teeth, or anywhere in between. Both placements are correct so long as the tongue stays at midline behind the teeth. Each individual will find which placement works best, however if children struggle with placement an interdental (between the teeth) lisp may result.
Manner of Production:
The /s/ and /z/ sounds are classified as “fricatives,” or pushing air out continuously through a small opening. Many children will have difficulty with the manner of /s/ and /z/ production, and will “lateralize” their airflow, resulting in a lateralized lisp.
/s/ and /z/ place and manner of production are identical, however these two sounds differ when it comes to voicing. /s/ is the voiceless pair to /z/’s voiced sound. For example, when producing an /s/ sound, our vocal chords are off (not vibrating), however when producing a /z/ sound, our vocal chords are on and vibrating. Try it – put your hand on your throat and feel the vibration when producing a /z/, and feel the difference when producing an /s/! Many children will understand the difference between the two sounds but may substitute one for the other.
If your child has difficult producing our “snake” sound (/s/) or our “bee” sound (/z/) a licensed speech-language pathologist can help!