sound off

verb

1. To hold forth about something in an opinionated manner.

   “I'm sick of his sounding off about how he thinks this country should be run!”

   “I would give anything to be at the hearing so that I could really sound off about this attempt to cram another liquor license into Jamaica Plain. I say kill it today.”

2. Command instructing a person to speak up or acknowledge something.

   “Hartman: […] Do you maggots understand that? Recruits: Sir, yes, sir! Hartman: Bullshit! I can't hear you. Sound off like you got a pair. Recruits: SIR, YES, SIR!”

3. Command instructing a person to confirm that they are present or that some other objective has been met.

   “Cyclops: […] X-men… Sound off … Man 1: Iceman, sounding off!Man 2: Fireman, sounding off! Man 3: Clothing-Man, sounding off! Man 4: Ability-to-Hop-Man, here!”

   “Tagon: Sound off! Brad, do you have the Ambassador? Brad: Check! Tagon: Schlock, do you have our money? Schlock: Check! Tagon: Are we still being pursued? Creeth Soldiers: Check!”