Isaac shouts, damaging and pushing away nearby enemies. The item can be used when not fully charged, and deals more damage and has increased range the more charges it has when used.
The initial shout deals 20 damage + 28 per charge and destroys enemy shots, obstacles, Shopkeepers, Beggars, and machines, and opens bombable doors in range.
A number of extra pulses are released equal to half the charges used (rounded up) that deal 2.5 damage + 3.5 per charge.
Larynx gains 1 charge whenever Isaac takes damage, as well as through normal means.
Notes
Larynx only has 1 charge when initially picked up.
Larynx will gain charges if Isaac is hit during the Mother's Shadow escape sequence.
Obstacles destroyed by the shout don't bridge gaps.
Synergies
Book of Virtues: Spawns red wisps on the middle ring. The wisps deals contact damage equal to 30% of Isaac's damage * Charges Used. Charges Used equals the number of charges Larynx had at the time it was used. Health = 1 * Charges Used. Tear Damage = 1.5 * Charges Used.
Habit: Both on-hit charge effects stack, charging 2 points per hit.
Hairpin: Fully recharges Larynx at the beginning of boss fights.
Interactions
9 Volt: The first bar gains an automatic timed recharge, but the further bars will not be affected.
The Battery: Larynx can hold up to two full charges. Only up to 12 charges will be used at a time.
Void: If Larynx is absorbed, its effect is only replicated at 1 charge.
Shopkeepers, 
Beggars, and machines, and opens bombable doors in range.
Mother's Shadow escape sequence.
Book of Virtues: Spawns red wisps on the middle ring. The wisps deals contact damage equal to 30% of Isaac's damage * Charges Used. Charges Used equals the number of charges Larynx had at the time it was used. Health = 
Habit: Both on-hit charge effects stack, charging 2 points per hit.
Hairpin: Fully recharges Larynx at the beginning of boss fights.
9 Volt: The first bar gains an automatic timed recharge, but the further bars will not be affected.
The Battery: Larynx can hold up to two full charges. Only up to 12 charges will be used at a time.
Void: If Larynx is absorbed, its effect is only replicated at 1 charge.
Everything Jar, 
Notched Axe, and 
Spin to Win are the only activated items that can be used when not fully charged.
Alabaster Box, 
Berserk!, 
Eden's Soul, and 
Tainted Samson Unlocks 
The Beast Unlocks 
The Binding of Isaac: Rebirth
