Speech Sounds

Articulation is the way we produce sounds. We use our tongue, lips, teeth, jaw and vocal folds to produce speech sounds. Children can experience a range of difficulties that will affect the way they produce their speech sounds.

Most children will make mistakes with their speech at some point in their development. Different sounds are expected to develop at different ages. A speech problem is when a child continues to make mistakes with a particular sound or group of sounds past the age expected.

Speech sound delays involve articulation errors (making the sound) and phonological process errors (sound patterns). A phonological delay will cause patterns of speech sound errors.

Speech Intelligibility is how well words can be understood by an unfamiliar listener (stranger e.g. a shop assistant)


  • AT 1 year: a child is 25% intelligible to strangers
  • AT 2 years: A child is 50% intelligible to strangers
  • At 3 years: A child is 70% intelligible to strangers
  • At 4 years: A child is 100% intelligible to strangers