Related Clues:

• Whispered message lead-in, perhaps
• Interruptive sound
• Cheater's whisper
• Surreptitious summons
• [I'm trying to speak here]
• Conspiratorial "Hey!"
• Conversation stopper
• Soft "Yoo-hoo!"
• ''If I may interrupt . . .''
• After thought, the saint said this for attention
• Sibilant "Over here!"
• Certain conversation starter
• ''Ahem'' alternative
• 'Could we get started, please ...'
• Sound before 3 Down, maybe