set status_voice [<text>]
This variable sets the string displayed in the status bar when the user has voice status in the current channel. If the user is not voiced, nothing is displayed. If the user is also a channel operator, then the value of STATUS_CHANOP is displayed instead.
This string is represented as %= in the STATUS_FORMAT string. It is taken literally in STATUS_VOICE, and has no special meaning.
Customizing the channel operator status indicator:
/set status_voice +