A useful distinction
A sound may signal a successful move, a warning or a time limit. Players who cannot hear it or have muted the device still need the information that affects play. Background music and essential feedback should be considered separately.
Put it into practice
List the sounds in a prototype and identify which communicate a rule-relevant event. Provide suitable visual or textual feedback for those events and test with sound muted. Do not assume that a volume control alone supplies an alternative way to understand the event.