What phonological error would result in a child saying "bub" for "bus"?

The response indicating assimilation as the phonological error when a child says "bub" for "bus" is accurate. Assimilation occurs when a sound in a word changes to become more like a neighboring sound. In this case, the final sound /s/ in "bus" is replaced by a /b/, which is more similar to the preceding /b/ in the initial position. This phonological process illustrates how children might simplify speech to better match familiar patterns or sounds, effectively adapting the word to their current phonetic capabilities.

Other phonological processes, such as fronting, stopping, and gliding, involve different types of sound changes that do not apply in this instance. For example, fronting involves the substitution of a sound produced at the back of the mouth, like /k/ or /g/, with a sound produced at the front, like /t/ or /d/. Stopping entails replacing a fricative sound (like /s/) with a stop sound (like /p/ or /b/), which doesn't align with this particular instance. Gliding refers to a substitute of /r/ or /l/ sounds with /w/ or /j/ sounds, which again does not relate to the situation where