From a list of possible error sounds, which sound is most likely to show early and rapid progress due to high input frequency and early age of acquisition?

• A. /k/
• B. /s/
• C. /v/
• D. /θ/

Answer: (A)

High input frequency and easy articulation favor sounds that emerge early and improve quickly. A velar stop like /k/ fits this well: it’s produced with a straightforward place of articulation at the back of the mouth, and it appears frequently in early babbling and everyday words, giving the child lots of practice. Because of that abundant exposure and relative articulatory simplicity, /k/ tends to be mastered earlier and show rapid progress. In contrast, the /s/ sound, while common in adult speech, requires precise frication and motor control, making it more challenging for early development. The /v/ sound is less frequent in early input and involves more complex voicing and articulation, and the interdental /θ/ is also typically late to acquire due to its place of articulation and perceptual demands.