The description of the zone of truth spell says:

you create a magical zone that guards against deception

But later on, it says:

On a failed save, a creature can't speak a deliberate lie while in the radius.

Say a character casts zone of truth on a mute person, or perhaps the party trickster simultaneously casts silence in the same area.
Under the mechanics of zone of truth, can an affected creature lie using sign language or a non-vocal form of communication?

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    \$\begingroup\$ A more simple example that doesn't even involve language per se would be: can you silently nod your head yes in response to a question when you know the answer is no? \$\endgroup\$ Apr 11, 2021 at 17:14
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    \$\begingroup\$ Sign language is a form of verbal communication. "Verbal" means that communication is accomplished through words. Sign language uses words, sentences, and other elements that make it decidedly verbal. \$\endgroup\$ Apr 11, 2021 at 17:52
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    \$\begingroup\$ Good point, I'm question is focused on communication without speech. Non vocal more clearly communicates me intent compared to non verbal. I've changed the question to reflect. \$\endgroup\$
    – Keverly
    Apr 11, 2021 at 19:57
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    \$\begingroup\$ Related English.SE question: Does one “speak” a sign language? \$\endgroup\$ Apr 11, 2021 at 20:09
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    \$\begingroup\$ @RyanC.Thompson That seems like a pointless question, in that nobody's going to cast Zone of Truth and then let you weasel out of speaking your answers. OP is envisioning casting it on someone who can't speak the answer, but then that raises the question of how you expect them to communicate an answer at all. I could see something like "Is the person who cut your tongue out sitting in this courtroom? If so, point to them"--does the spell prevent them from pointing to the wrong person? \$\endgroup\$
    – Mark Wells
    Apr 11, 2021 at 20:35

6 Answers 6


Sign language will be at the GM's discretion.

As you noted, the effect of Zone of Truth is:

On a failed save, a creature can’t speak a deliberate lie while in the radius.

There are no explicit rules for sign language in 5e. It isn't provided as a language that may be learned, and it isn't incorporated into existing rules. There are some mentions of NPC sign language (such as Drow Sign Language). If your GM is allowing for sign language, you are in their territory.

Non-Verbal Communication May be Deceitful

The first sentence of Zone of Truth says:

You create a magical zone that guards against deception ...

This does not imply that it prevents every kind of deception. The specific effects are listed later ("a creature can't speak a deliberate lie"). The effect of preventing deliberate spoken lies is how it guards against deception.

Non-verbal communication may be deceitful. Zone of Truth regulates "speak[ing]". Non-verbal communication includes things like body posture, facial expressions, and other non-spoken contextual things.

If a regicide under Zone of Truth is asked, "did you kill the King?" they are not allowed to speak a lie. However, they can feign a surprised or innocent expression and body language to support it.

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    \$\begingroup\$ Heck, even verbal communication can be deceitful without speaking a lie, if the speaker is clever enough. \$\endgroup\$
    – Carmeister
    Apr 12, 2021 at 5:06
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    \$\begingroup\$ "Wha... what?! Me?! Kill the King?! I... I... (stammers at a loss for words with a deer in the headlights look on their face)" P.S. See "The Wheel of Time" by Robert Jordan. \$\endgroup\$
    – Vilx-
    Apr 12, 2021 at 6:15
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    \$\begingroup\$ "Well, no, I didn't kill the king, of course (since I killed the previous king, and the king is now his heir, who is pretty much alive as you can see)" \$\endgroup\$ Apr 13, 2021 at 9:51
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    \$\begingroup\$ Naïve interrogation: The interrogator foolishly assumes ZoT is reliable as-is. Skilled interrogation: The interrogator is experienced at interrogation. Likely has high charisma score, naturally or via buff. Can theoretically be fooled by misleading phrasing, but this is difficult. Brute force interrogation: Interrogator says things like, "You have 10 seconds to respond. State: 'I did not attempt to kill the king.' Failure to use this exact wording and you will be beheaded immediately." Brute force interrogation offends/angers the person being interrogated. \$\endgroup\$
    – Brian
    Apr 13, 2021 at 15:32
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    \$\begingroup\$ If you are told to state the phrase "I did not attempt to kill the king", and you do, is that a lie or a truthful repetition of a quote? \$\endgroup\$
    – mattdm
    Apr 13, 2021 at 22:34

I agree that they can lie non-verbally, as the rules specify the the target cannot speak a lie.

However, even if they can, the conjurer knows their own magic and will probably just tell others "They need to speak, or else the spell won't work, do not trust their gestures!"

They could also just refuse to answer the question. "I do not want to answer this question", as the spell per se does not compel anyone to speak.

So...not much use for that in a practical way. The conjurer and interest parts will probably view this as elusive attempt to hide the truth, and it will have the opposite effect, most probably.

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    \$\begingroup\$ I love thinking about ways how this could go wrong. Imagine a ... less than honest party using this to manufacture evidence against a suspect. Asking the right loaded questions will make the suspect look really suspicious even if they are purposefully never directly asked if they actually did the deed. \$\endgroup\$
    – xLeitix
    Apr 12, 2021 at 11:52
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    \$\begingroup\$ "Did you hate X?" "Did you ever dream about killing X?" "Isn't it true that your alibi for the time of X's death is incorrect, and you were indeed alone at that time?" ... sorry, spell duration is over, as the jury can clearly see the suspect is guilty. Case closed. \$\endgroup\$
    – xLeitix
    Apr 12, 2021 at 11:54
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    \$\begingroup\$ (or the other way round, now, that I think about it - "Me, killed X? Most certainly not. [My buddy Frank lobbed his head off, I just poked him in an almost certainly not immediately lethal way with my sword.]") \$\endgroup\$
    – xLeitix
    Apr 12, 2021 at 11:59
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    \$\begingroup\$ Even with malicious questions, nothing would keep the framed suspect to tell the truth...think about it: "Did you hate X? Did you ever dreamed about killing X?" "Yeah, i did...but i did not killed him." However, if a not-so-honest party member is the caster, he could always say "Yeah... he resisted the spell..." XD \$\endgroup\$ Apr 12, 2021 at 13:12
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    \$\begingroup\$ I did not kill the King! [I stabbed him repeatedly and then he bled to death]. \$\endgroup\$ Apr 12, 2021 at 14:54

Yes, you can lie non-verbally if you fail a ZoT save

The magical zone created by ZoT guards against deception:

You create a magical zone that guards against deception

But there are multiple ways of satisfying that description. ZoT does not have to guard against all deception, or eliminate every possibility of deception. It just guards against deception.

The way in which ZoT 'guards against deception' is made clear by the rest of the spell's description:

On a failed save, a creature can't speak a deliberate lie while in the radius

So the spell guards against deception by stopping those under its influence from speaking a deliberate lie. That's the specific remit of the spell's guarding; accidental lies (whatever those are), hand-signals and written words are outside of the scope. If a spell does something, it's in the spell's description. If something's not in the spell's description, the spell doesn't do that thing.

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    \$\begingroup\$ An accidental lie is when the speaker is unaware of the truth, or possibly unaware that the interpretation given his words will not match his intent. \$\endgroup\$
    – Mary
    Apr 11, 2021 at 20:59
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    \$\begingroup\$ @Mary The word "lie" is usually reserved for intentional deception by definition, which is why an accidental lie in the sense you describe is in fact not a lie at all. I could imagine that is exactly what Lovell alluded to by saying "whatever those are". \$\endgroup\$ Apr 11, 2021 at 22:49
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    \$\begingroup\$ An example of "accidental lie": You see a drow killing a man... you don't know, but it is a dwarf using a illusion spell to change his appearance. If someone ask you "who killed this man?", and you answer "the drow killed him", you are not lying, but this ain't truth either... \$\endgroup\$ Apr 11, 2021 at 23:44
  • \$\begingroup\$ @AlanRégis Is that not just "being wrong" rather than a lie of any sort? \$\endgroup\$ Apr 14, 2021 at 13:14
  • \$\begingroup\$ @Pilchard123 yes it is... i would say that an accidental lie is when you don't know you're not speaking the truth for a number of reasons (ignorance, confusion, or wrong interpretation of the question). Something like: Is it true that the affirmation that "you did not fail to miss the chance to not help the young lady to not commit the murder" is incorrect? Easy to get confused and give the wrong answer by accident. XD \$\endgroup\$ Apr 14, 2021 at 14:23

I dare say that because the way they worded the effect:

On a failed save, a creature can’t speak a deliberate lie while in the radius.

That they actually intended for players to be able to feel smart about themselves and think ‘ohh they say speak!’

The people behind D&D have plenty of experience with how phrases in rules are overanalyzed. They could have easily just said ‘can’t lie deliberately’ but instead they chose to include ‘speak’ in the sentence.

I would say it’s not even up to the GM (other than everything being up to the GM in the end) but it’s just flat-out possible to lie non-vocally. However, the (n)pc’s who know the effect of the spell might see through that.

  • \$\begingroup\$ Signing is non-verbal, and yet one can easily lie in sign. \$\endgroup\$
    – NomadMaker
    Apr 12, 2021 at 14:06

By RAW, you can lie non vocally in a Zone of Truth.

The Zone guards against deception. PHB page 178 states

Your Charisma (Deception) check determines whether you can convincingly hide the truth, either verbally or through your actions.

In the spell description of Zone of Truth, they are not referring to Deception the skill, but the definition of the skill lines up fairly well with the english language definition, which states that deception is the act of decieving someone, and decieve is defined as making someone believe something that is not true, with no mention of having to speak.

This means deception does not have to be vocal, or even verbal. However, there is some ambiguity. You cannot speak a deliberate lie. Speaking clearly means talking, making a sound with your voice in a certain language. Body language, sign language, and pantomime are not speaking.

By RAI, you cannot lie non vocally in a Zone of Truth.

They say speak a deliberate lie, yes, and RAW must interpret every word of the spell description. However, it seems obvious to me that they intended no deception to be possible, as shown in the earlier line.

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    \$\begingroup\$ @MarsPlastic It's a great question, and I will refer you to a related question on Linguistics. It sounds like it's appropriate to talk about sign language having phonemes, despite not being spoken. IANAL (i am not a linguist). \$\endgroup\$ Apr 11, 2021 at 23:39
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    \$\begingroup\$ I don't find the "RAI" segment of the answer very convincing; it doesn't necessarily seem "obvious" to me that "they intended no deception to be possible" (and the answer doesn't provide any further support for this claim other than simply pointing back at the first line of the spell description. A character can be deceptive without speaking a deliberate lie; the easiest example of this to me is a "lie of omission" (i.e. providing certain information while withholding other information). This would not violate the restrictions of zone of truth. \$\endgroup\$
    – V2Blast
    Apr 12, 2021 at 1:34

No. Silence can speak volumes.

Speaking is not defined in the rules; accordingly, we must look to common usage.

According to the Oxford Dictionary, the definition of "speak" is as follows:

  1. say something in order to convey information, an opinion, or a feeling. "in his agitation he was unable to speak"


  1. (of behavior, an object, etc.) serve as evidence for something. "his frame spoke tiredness"

Accordingly, body language is speaking as much as verbal speech is speaking.

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    \$\begingroup\$ Definition 2 is clearly figurative, not literal. Most objects don't actually speak, even when they "speak volumes". \$\endgroup\$ Apr 11, 2021 at 17:10

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