If your child says “thun” for “sun” or their S sounds slushy, they may have a lisp. Lisps are one of the most common speech patterns in childhood, often charming in a toddler, but worth understanding so you know whether to wait or to act.
What a lisp is
A lisp is a type of speech sound disorder that affects the S and Z sounds, usually because of how the tongue is placed. There are a few different types, and the type matters for treatment.
The main types of lisps
- Frontal (interdental): the tongue pushes between the front teeth, turning S into a “th” sound (“thun” for “sun”). This is the most common and is developmentally normal in young children.
- Lateral: air escapes over the sides of the tongue, giving S a wet, slushy quality. This one is not a normal developmental stage and usually needs therapy.
- Palatal: the tongue contacts the roof of the mouth, distorting the sound.
- Dental: the tongue pushes against (rather than between) the front teeth.
What causes a lisp?
Most lisps come down to tongue placement and habit as speech develops. Others can be influenced by things like prolonged thumb-sucking or pacifier use, dental alignment, or tongue-tie. In many young children, a frontal lisp is simply part of learning and resolves with time.
When is it normal, and when to treat?
A frontal lisp is often typical up to around age 4 to 4½ and frequently fades on its own. It is worth an evaluation when a frontal lisp persists past that age, or right away for a lateral lisp, since those rarely resolve without help and are easier to correct earlier than later.
How therapy helps
Speech therapy for a lisp is highly effective. An SLP teaches your child exactly where to place the tongue and airflow for a clean S, then practices it into words, sentences, and everyday speech. It is one of the more satisfying things to treat because progress is usually clear. If your child’s lisp has stuck around, see how we work with kids and families or book a free consultation to get started.
Not sure where to start?
Take our free 2-minute screener to see whether speech therapy could help, no sign-up, no cost. Or book a consultation to talk it through with a licensed SLP.