| Age (average) | Sound | Example |
|---|---|---|
| Three years old | /d/ /g/ /b/ /t/ /k/ /p/ /m/ /n/ /ng/ /w/ /y/ /zh/ /h/ | Dog Girl Bat Tall Cat Pen Neat Sing Water Yellow Measure Hello |
| Three and a half years old | /f/ | Friend |
| Four years old | /ch/ /sh/ /l/ | Chicken Brush Like |
| Four and a half years old | /s/ /z/ /j/ | Sail Lizard Jelly |
| Five years old | /r/ | Red |
| Six years old | /v/ | Vegetable |
| Eight years old | /th/ | This |
| Eight and a half years old | /th/ | Thing |
| Phonological process | Explanation | Example | What age it usually disappears (on average – guide only) |
|---|---|---|---|
| Voicing | When sounds that don’t need much vocal power are emphasised | /t/ becomes /d/ (‘time’ becomes ‘dime’) | Three years old |
| Fronting | When sounds that usually are made at the back of the mouth are instead made at the front | /k/ becomes /t/ (‘cat’ becomes ‘tat’) | Three and a half years old |
| Stopping | When long sounds are replaced with short sounds | /s/ becomes /t/ (‘see’ becomes ‘tee’) | Three to five years old |
| Cluster reduction | When two consonant (non-vowel) sounds that usually sit together are reduced to one consonant sound | /st/ becomes /t/ (‘stop’ becomes ‘top’) | Four years old |
| Final or initial consonant deletion | When the first or last consonant sound in a word is removed | /p/ drops off in ‘top’ | Four years old |
| Weak syllable deletion | When syllables that don’t need much stress are forgotten in words | /le/ drops off in ‘elephant’ to become ‘ephant’ | Four years old |
| Gliding | When sounds requiring the tongue to be in the correct place are sometimes not | /r/ becomes /w/ (‘rabbit’ becomes ‘wabbit’) | Five years old |
