Stopping involves which of the following?

Stopping is a phonological process where a fricative or affricate sound, which is produced with a continuous airflow, is replaced by a stop consonant, which obstructs airflow completely. In this context, when a sound like /f/, /s/, or /ʒ/ is substituted with a stop sound such as /p/, /t/, or /k/, it illustrates the process of stopping. This process is commonly observed in children as they develop their speech and may happen as a simplification strategy.

For instance, a child might say "tun" instead of "sun," which demonstrates how the fricative /s/ is stopped and replaced with the stop /t/. This pattern adheres to the definition of stopping, making the identification of the fricative or affricate being replaced with the stop sound crucial to understanding this phonological process.