stumble
蹉 centers on the act of stumbling or tripping, both literally and figuratively.
蹉 combines 足 (foot) with 差, which likely contributes the sound and suggests an uneven or differing step, leading to stumbling.
The left side is 足 (foot), and the right side is 差 (difference). Imagine a foot encountering an unexpected difference in the ground, causing a stumble.
For サ, picture a person stumbling on a sandy path: the sand (サ) makes the footing uneven, and the foot 足 catches on the difference 差.