Speech sound substitutions
Children often substitute easier sounds for more difficult ones when they are learning to talk. Here are some common sound changes that usually go away as children get older:
| Sound substitution | What happens | Age usually resolves |
|---|---|---|
| Voicing | Producing a voiceless sound as a voiced one, i.e. a quiet sound is said as a louder one e.g. ‘p’ becomes “b”, ‘t’ becomes “d”, s becomes “z”’. This means for example, pie becomes “bye”; tea becomes “dee”, see becomes “zee” | Typical until about 3 years of age |
| Stopping | Long sounds are replaced with short sounds. For example: sun becomes “tun”, zoo becomes “doo”, bees becomes “beed”, dizzy becomes “diddy” | Typical until about 3 ½ years of age |
| Final consonant deletion | The last consonant sound of a word is missed off. For example: bat becomes “ba_”, pen becomes “pe_”, leaf becomes “lea_” | Typical until about 4 years of age |
| Fronting | The k and g sounds which should be produced at the back of the mouth, are replaced with sounds produced at the front: t and d. For example: car becomes “tar”, bag becomes “bad”, foggy becomes “foddy” | Typical until about 4 years of age |
| Weak syllable deletion | The unstressed syllable of a multisyllabic word is missed out. For example: banana becomes “nana”, octopus becomes “ocpus”, butterfly becomes “buttfly” | Typical until about 4 years of age |
| Cluster reduction | A ‘cluster’ is 2 or 3 consonants together in a word. Cluster reduction is when one of these sounds is not produced. For example: blue becomes “boo”, flower becomes “fower” snail becomes “nail” | Typical until about 5 years of age |
| Deaffrication | Complex sounds such as ch and j are replaced with easier sounds such as t, d, s. For example: joy becomes “doy”, cherry becomes “serry”, watch becomes “wats” | Typical until about 5 years of age |
| Gliding | Replacement of r with w and l with y. For example: Red becomes “wed”, long becomes “yong”, spring becomes “spwing” | Typical until about 6 years of age |
| Sound substitution | What happens | Age usually resolves |
|---|---|---|
| Voicing | Producing a voiceless sound as a voiced one, i.e. a quiet sound is said as a louder one e.g. ‘p’ becomes “b”, ‘t’ becomes “d”, s becomes “z”’. This means for example, pie becomes “bye”; tea becomes “dee”, see becomes “zee” | Typical until about 3 years of age |
| Stopping | Long sounds are replaced with short sounds. For example: sun becomes “tun”, zoo becomes “doo”, bees becomes “beed”, dizzy becomes “diddy” | Typical until about 3 ½ years of age |
| Final consonant deletion | The last consonant sound of a word is missed off. For example: bat becomes “ba_”, pen becomes “pe_”, leaf becomes “lea_” | Typical until about 4 years of age |
| Fronting | The k and g sounds which should be produced at the back of the mouth, are replaced with sounds produced at the front: t and d. For example: car becomes “tar”, bag becomes “bad”, foggy becomes “foddy” | Typical until about 4 years of age |
| Weak syllable deletion | The unstressed syllable of a multisyllabic word is missed out. For example: banana becomes “nana”, octopus becomes “ocpus”, butterfly becomes “buttfly” | Typical until about 4 years of age |
| Cluster reduction | A ‘cluster’ is 2 or 3 consonants together in a word. Cluster reduction is when one of these sounds is not produced. For example: blue becomes “boo”, flower becomes “fower” snail becomes “nail” | Typical until about 5 years of age |
| Deaffrication | Complex sounds such as ch and j are replaced with easier sounds such as t, d, s. For example: joy becomes “doy”, cherry becomes “serry”, watch becomes “wats” | Typical until about 5 years of age |
| Gliding | Replacement of r with w and l with y. For example: Red becomes “wed”, long becomes “yong”, spring becomes “spwing” | Typical until about 6 years of age |
If a child continues to make a specific sound change 6 months beyond the usual age, consider asking for help from a Speech and Language Therapist.
There are some sound substitutions which children make that are unusual
Initial Consonant Deletion: The first consonant sound of a word is missed off. For example: car becomes “ar”, boat becomes “oat”, fall becomes “all”
Backing: Sounds such as t, d, n, which should be produced at the front of the mouth, are replaced with sounds produced at the back – k, g, ng. For example: two becomes “coo”, door becomes “gore”, train becomes “crane”; sing becomes “sin”
Vowel Errors: Difficulty saying vowel sounds correctly in words. For example:. bird becomes “bord”, baby becomes “bebby”, toy becomes “tor”, light becomes “lart”
Lateralisation: Speech sounds ‘slushy’ as air escapes from the sides of the mouth. This particularly affects the s and z sounds.
If your child is showing any of these unusual patterns, refer to Speech and Language Therapy.
Some children make some sound changes which don’t impact understanding much. We would not routinely accept referrals for the following, but you can ask for advice through our telephone advice line:
- Interdental lisp – placing the tongue in between the upper and lower sets of teeth when saying s and z sounds such as sun becomes “thun” and fuzzy becomes “futhy”.
- Replacing r with w. For example, rubbish is said as “wubbish” and robot is said as “wobot”.
- Missing ‘t’ in the middle and at the end of words.
- Substituting ‘f’ for ‘th’ for instance teeth is said as “teef” and think is said as “fink”.
Why do some children make sound changes?
For most children, there is no clear reason why they have difficulties saying some sounds.
For other children, there are clearer reasons:
- Delayed language and communication skills. Children’s pronunciation development depends on developing other skills. If their attention, understanding, sentence formation or social skills are delayed, their speech sound development may be delayed too.
- Muscle control difficulties, like those in cerebral palsy or dyspraxia, can affect the muscles needed for forming sounds.
- Hearing difficulties can affect pronunciation development. Watch out for children who have lots of ear infections and colds and seek advice from a GP.
- Physical differences in the structure of the mouth, like cleft palate, can affect how speech sounds are made.
How can you help your child’s pronunciation develop?
- Model the correct pronunciation of words your child has difficulty saying. For example, if the child says, “Can I have dink?”, you say “Yes, of course, let’s get you a drink” or if the child says “The ‘puter is broken”, you say “The computer is broken. Oh no!”
- Don’t tell your child they are mispronouncing sounds or ask them to copy you. Simply model back the correct pronunciation.
- Encourage your child to look at your mouth when you model correct pronunciation so they can see where you place your tongue, teeth and lips.
- Play sound games like I spy, focusing on the sound the child has difficulty saying, rhyming games like “what words do we know that sound like hat? hat, bat, mat…”, clapping out the number of syllables in words and identifying words that begin with the same sound.
- If you cannot understand what your child is saying, look around to see what they might be talking about. Encourage your child to use non-verbal methods like pointing, taking you to the thing they are talking about or using gestures to help you understand.
- Give your child lots of praise to build their confidence.
- Ask your child questions that need a yes, no or very short answer to help clarify what they are saying. For example, “Are you telling me about Daddy?” or “Are you talking about painting or cutting and sticking?”
- Use strategies to help guess what your child might say. For example, using a home-school book where parents can record events or weekend activities, or use books, pictures, models etc. These can help if your child’s speech is very unclear because you have some idea of what they might be trying to say.
Further sources of support
Last reviewed February 2026