In what order do the phonemes /p/, /θ/, /k/, and /ʒ/ typically get acquired?

The order of phoneme acquisition reflects the typical progression in speech development among children. In this context, the phonemes /p/, /θ/, /k/, and /ʒ/ represent a variety of places and manners of articulation, which influence their ease of production.

The phoneme /p/ is a bilabial stop, produced using both lips, and is usually one of the earliest sounds children acquire due to its simplicity and ease of articulation. Following /p/, the phoneme /θ/, which is a voiceless dental fricative, tends to develop later as it requires precise tongue placement against the teeth. The production of /k/, a velar stop, often develops around the same time as /θ/ since both require some degree of airflow control and oral closure. Finally, /ʒ/, a voiced postalveolar fricative, typically emerges last because it involves a more complex articulation and is less frequent in the initial positions of words.

Thus, the sequence /p/, /θ/, /k/, and /ʒ/ accurately reflects this developmental pattern, aligning with the evidence from normative speech development studies.