Positive and negative effects of being permanently deaf PC

Question

I'm creating a deaf Fighter for a campaign, which I hope will last a while (10-12 sessions). The DM has allowed it, but we have not yet agreed on how the deafness affect my PC mechanically (I used gestures and sign language known only by the party, kind of home sign language, for the roleplay). However, we have agreed that the deafness must have a meaningful impact to the PC mechanically.

This answer suggest that there are both pros and cons being deaf. Except failing ability checks that require hearing, what is the complete list of other effects (both positive and negative) of being deaf?

Things I'm not sure of is whether there is penalty to passive and active perception and when casting spell (I heard there is failure chance?)

Answer 1

I am a hard of hearing person, this is how I would translate my experience into the game

Ability Checks

• Advantage on all perception checks based on vision
• Automatic fail on perception checks based solely on hearing (your DM would decide when the sound would be felt by you in which case it would be at disadvantage)
• Disadvantage on persuasion, deception, and intimidation when speaking
• Advantage on insight
• Either normal passive perception or two different passive perceptions one boosted and one lowered that your DM would pick based on the situation.

Languages and Communication

• Ability to lip-read any language you know
• A sign language on top of the other languages that you know
• Silent communication
• Communication between translucent barriers or long distances

Spells

• All attacks against you that are based on sound fail
• No effect on spellcasting and your DM can decide if verbal spells can be cast with sign language if it impacts roleplay.

Other

You and your DM can decide how prevalent your sign language is, and if there is discrimination against the deaf.

You can also decide if you have magic hearing aids, and how those work: Perhaps disadvantage on hearing perception checks instead of automatic fail with a chance of malfunction or needing to charge them

What exactly your character's background is will affect the mechanics. Please ask if you want any explanation or have any questions on role-playing the deaf character.

Answer 2

5e doesn't specify how to simulate this, so it's up to the DM

5th edition assumes that Deafened condition is temporary (hence the name) and, unlike the previous versions, have little mechanical downsides for it. There is no failure chance when you cast a spell being deafened in 5e. There was one in 3.5e/Pathfinder though:

a spellcaster who has been deafened has a 20% chance of spoiling any spell with a verbal component that he tries to cast

Possible RAW mechanical downsides of being deafened in combat were already discussed in this question: How does deafness affect melee combat?

There is no rules-as-written penalty to Perception check either, since 5e almost got rid of any check penalties, using disadvantage mechanics instead. You just can or can not perceive something, depends on the sense used (sight or hearing). The final verdict is always up to the DM. The DM might skip the check, or impose a disadvantage if they thinks it is necessary.

The rules in 5e don't explicitly codify many things. The DM is encouraged to use common sense instead and apply disadvantage when it is appropriate. For instance, if your group doesn't use the Flanking optional rule, it can be used for the deaf person exclusively, since he have troubles hearing enemies creeping from behind.

There are almost no advantages of being permanently deaf

The implications of being deaf are pretty obvious, although it's hardly possible to make "the complete list". A deaf person can't hear anything. Many "negative effects" would be narrative rather than mechanical ones (this can be applied to 5e in general). For instance, you can't hear people talking - so no eavesdropping, no bargaining nor gathering information in taverns, no parleying with goblins, etc.

Having the sign language known only by the party isn't the positive side of being deaf. It's a positive side of knowing such a language — you don't have to be deaf to know it.

The only positive side of deafness is the immunity to any spells requiring the target to hear. For example, the Dissonant Whispers spell explicitly says it doesn't work on deafened targets:

A deafened creature automatically succeeds on the save.

There are other spells, requiring "a creature that can hear", like Suggestion:

You suggest a course of activity (limited to a sentence or two) and magically influence a creature you can see within range that can hear and understand you.

PH has a few spells with this requirement:

• Animal Friendship
• Compulsion
• Dissonant Whispers
• Divine Word
• Enthrall
• Suggestion/Mass Suggestion
• Tongues (this one actually has a positive effect)
• Vicious Mockery

Additional features using this requirement:

• Bardic Inspiration (also have a positive effect)

Answer 3

There are none, other than what you have already listed. Being deaf means failing any checks related to hearing and not being able to hear, and that's it. The rules about spell failure are from a previous edition. There's no penalty to perception (you just auto-fail any sound based checks, but the rest is fine).

Of course, there are a lot of "mechanical" interactions that will occur in your games that aren't really easily caught in a plus or minus to something. Not being able to hear means your character cannot be woken easily when your party is ambushed at night, means you'll have a hard time finding out what's behind a door without opening it and makes spotting an invisible creature really difficult (since listening to their footsteps in normally the way you find them if you can't see them)

There's also some upsides, though. There's some spells that specifically call out that the target needs to be able to understand you, like Command. There's also monster effects based on sound that you would probably be immune to.

But as for hard, mechanical penalties, there's nothing beyond "you can't hear".