I remember reading about how a lot of the early paleolithic societies and proto-human species like Neanderthals and Homo Erectus used sign languages before spoken languages. It made me wonder how a society that never developed spoken language would be like.

Let's say that 100,000 years ago, Homo Sapiens dies out but a new species by the name of Homo Mutus takes over. Homo Mutus is very similar to Homo Sapiens. The difference is that they require less food than Homo Sapiens but they also lack a voicebox. Homo Mutus cannot speak, scream, whisper, or make any non-chewing sounds with their mouth.

Can Homo Mutus develop an advanced civilization like Homo Sapiens has without spoken language? Will it be harder or easier to do so with everybody having to use sign language and written languages instead of speaking to get points across?

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    $\begingroup$ Sign languages are as rich as spoken languages, so why not? $\endgroup$
    – Jon Custer
    Oct 6, 2022 at 17:01
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    $\begingroup$ people keep bringing up that you can’t use sign language in cases where you can’t see the other person. But you can’t speak under water or in a vacuum. You can’t speak if your mouth is covered or if the listener is temporarily deafened. You can’t listen well if there are loud noises around you. You can easily not hear things if you are distracted. However that has not stopped people from using spoken language to achieve communication. In the same way those who use sign language can achieve communication in spite of the challenges they face. $\endgroup$
    – user64888
    Oct 6, 2022 at 20:34
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    $\begingroup$ Please clarify, "Sign Language' or 'finger spelling'? They are very different forms of a language. The main drawback of Sign Language is the lack of a written language. There are no phonemes to translate into written symbols. Even those who use Sign Language exclusively, usually fall back on a 'spoken word' written language. Perhaps the best analogy to a written 'sign language' would be hieroglyphics, where the pictograms represent signs instead of spoken words. This leads to the conundrum of using pictographs for mathematical and chemical shorthand in equations. $\endgroup$ Oct 7, 2022 at 0:58
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    $\begingroup$ @JustinThymetheSecond Sign languages absolutely do have phonemes and can be written. (I know, it's etymologically confusing, but calling them "cheremes" is out of style these days.) The fact that they mostly aren't is an artifact of the primacy of oral language in humans. And the Chinese don't seem to have had any trouble with mathematics despite using a logographic writing system. $\endgroup$ Oct 7, 2022 at 1:38
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    $\begingroup$ Not having vocal folds doesn't mean one can't talk. They can still whistle, and there are whistling languages; they can still whisper, which means they can physiologically talk. Also, and this is very important: please edit your question to include the criteria by which you would judge an "advanced society". $\endgroup$
    – elemtilas
    Oct 7, 2022 at 2:52

8 Answers 8


Sign language can be better

Although there are plenty of situations where sign language would be worse, I think it can actually be better than spoken language.

The idea is that language is required or at the very least boosting a group's ability to advance. This is because the knowledge can spread. As Newton is claimed to once write about his scientific progress: "if I have seen further, it is by standing on the shoulders of giants". The important factor here is that the type of language is less of a factor. We can see in our current society that speech is a definitely great way to spread knowledge and we have done so for millennia. Interestingly it was improved by the written word. But both are still derived from language. In that regard sign language has enough variation and expression to have similar knowledge transfer. Even in this society you can speak volumes by just lifting your middle finger.

The drawbacks are that it is more difficult in groups for example. People need to face the person, as well as see all the different gestures that are made. However, such arguments are easily made from a speaking society. A sign language society could have many advantages compared to the spoken language.

First if all is attention. We can more easily feign attention of listening, while you are much more limited in sign language. This allows for more concentrated 'talking' with sign language. In addition, such a society is more likely to notice a lack of attention, making pauses and breaks important to sign language. They resume when attention can be focused again. This helps in getting a point across better. Teaching might look at a disadvantage, as you can probably service less people in a classroom as a teacher. However, this would lead to more teachers and thus more personal and intensive teaching.

But the shortcomings of language can also increase the importance of language. An example. If you're hunting a large predator or other humans it is extremely important to know what needs to happen beforehand. That means they would improve their language skill as a consequence. Then during a fight where any plan can go right out the door you need to be able to communicate quick and clear what needs to happen. Without a voice and possibly with one or both hands full you would be hampered. So with as few short 'words' you need to be able to communicate. Most probably claps of hands or weapons in certain ways.

Interestingly the best way of communication in many close quarters fighting is silent, often up until the moment you engage.

The language has shortcomings that can be overcome by a surge in communication. This can be compared to an earlier time where many human tribes had a less vocabulary. Out of necessity you create new words to describe and talk. If the necessity is greater there is a larger chance of evolving the language.

That is not to say they will succeed. The shortcomings will at first work against them. It'll take quite some time before it can work in their favour, but at the very least they are more likely to grow their language skills faster than a spoken language out of necessity. At a later time they will reap those rewards.

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    $\begingroup$ Good answer (+1), I'd suggest 2 improvements. 1) mention Albert Mehrabian and subsequent studies on non-verbal communication en.wikipedia.org/wiki/Albert_Mehrabian to augment argument they may communicate better face to face. 2) the big disadvantage is not surviving the night but rather instruction in practical skills. If a person is trying to teach a skill where the participant must be looking elsewhere eg rock climbing, tightrope walking, or flying an aircraft, it is impossible to give feedback during practice, only before and after. $\endgroup$ Oct 6, 2022 at 22:13
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    $\begingroup$ Babies are able to sign before they can speak (en.wikipedia.org/wiki/Baby_sign_language), so another possible advantage is that language development can start earlier (and perhaps be less frustrating?) $\endgroup$
    – Ottie
    Oct 7, 2022 at 7:52
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    $\begingroup$ Another upside: communication over longer distances is possible, using binoculars or telescopes instead of electrical cables (which were invented hundreds of years later). $\endgroup$
    – kaya3
    Oct 7, 2022 at 11:13
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    $\begingroup$ In regards to your comment on group communication, my experience is that signed languages can actually be superior for that in that it is much easier for multiple people to be communicating at once, in separate conversations, without having to "speak over" the others. $\endgroup$ Oct 7, 2022 at 12:34

The more technological a society becomes, the less a spoken language matters

I don't know about you, but the further along my educational road, the less a spoken voice mattered. I had lots of textbooks, research on the Internet, math and graphing programs, circuit design and simulators... Need I go on? Things were already visually symbolic. In fact, here we are sharing ideas with nary a phonon in sight. And those aspects of my education that depended on the spoken word (study groups and lectures) could have been trivially converted to sign language.

I can't think of any reason at all why sign as a primary — or even the sole — language would stop a society from becoming as advanced as any other.

I can tell you one other place it would be an incredible benefit. Sports! Specifically baseball... no more "Hey! Batter, batter, batter!" distractions. I'm right, right?! Think about it.

And now that I think about it, theatre might become visually amazing. We humans pride ourselves in the expressiveness of our dance... but can you imagine how breathtaking a stage production would become? It gives a whole new meaning to "body language."

And what's really amazing is if a soceity evolved based on it, it would be as natural and as capable as any other language. Don't be fooled by what its limitaitons might be compared to our evolution based on sound. Knowing no other way, they would be as capable as we. I wonder how that would affect the development of their peripheral vision?

  • $\begingroup$ Knowing when to step away from a pointless discussion is a wonderful skill. $\endgroup$
    – L.Dutch
    Oct 9, 2022 at 18:17

The only shortcoming I can imagine for a pure sign based language is that it will not allow communications in situation where there is no visibility between the sender and the receiver: for example the darker hours of the night or a situation in which they are not looking at each other.

I think that it is severely limiting: if a bear is attacking you, your and your companion's attention will be focused on the bear, not on your hands so you won't be able to help each other with directions, or if you are walking in line and you are leading the line you have to decide if you want to keep your attention to the path or turn around and talk with your team, nor your followers will be able to warn you of any danger coming from behind. Or during a fight you will have to pick between using your hands for fighting or communicating.

I doubt such a limited communication will help advancing easily.

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    $\begingroup$ They're mute, not deaf. Snapping, clapping, hand-rubs, and all sorts of non-vocal audio signals are still on the table (and in fact, Hearing CODAs--Children Of Deaf Adults--do learn to distinguish the incidental audio signatures of certain sign categories). And darkness is not problem as long as you can get together and touch for tactile signing. $\endgroup$ Oct 6, 2022 at 17:20
  • $\begingroup$ Clicks are also possible (languages like Khoi-San make some use of them). $\endgroup$
    – LSerni
    Oct 6, 2022 at 18:09
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    $\begingroup$ Longer range auditory signalling could be based on whistling, which (to my limited knowledge of human anatomy) does not require a voice box or vocal cords. The use of whistling for communication at a distance is practiced by various cultures around the world, for example in mountainous regions. $\endgroup$
    – njuffa
    Oct 7, 2022 at 2:31
  • $\begingroup$ @njuffa "OMG there's a bear coming out of the woods!! Quick, get your bow and arrows while I tend to Thag's wounds." There's no way in heck a whistling language can transmit that anywhere near as quickly as a spoken language. $\endgroup$
    – RonJohn
    Oct 8, 2022 at 2:45
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    $\begingroup$ @RonJohn Military groups have been getting away with military signs to be able to communicate things like "get your bow and arrows while I tend to Thag's wounds" silently, all the while avoiding being heard by an enemy. $\endgroup$
    – Stef
    Oct 8, 2022 at 8:35

Sign language is a language

Any transfer of information that happens orally can happen with sign language, new words and grammar can and have been added to sign languages around the world to keep up with modern technology.

Furthermore, the in an advanced modern society most information transfer is written or comes with written components. So speaking versus signing won’t change much.

Again, sign language is a language.

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    $\begingroup$ This sort of suggests that any system of communication with a sufficiently large expressive capacity is more-or-less equivalent, but glosses over the practical aspects of the system. Yes, you can in principle express anything said with oral communication via sign language, but that's certainly not true in practice - you can't sign to someone not looking at you, as a simple example. That two languages have equal expressive capacity doesn't imply they are equally practical. Binary computer code is also a language, but I doubt it would lend itself to effective communication between humans. $\endgroup$ Oct 6, 2022 at 19:12
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    $\begingroup$ @NuclearHoagie the asker is asking if the species can make an advanced civilization. That doesn’t necessarily require the ability to communicate perfectly in emergency situations. It only requires the ability to transfer information effectively, which sign language can do. Also, this society has writing, which means that all advanced technical communication is still written. $\endgroup$
    – user64888
    Oct 6, 2022 at 20:39
  • $\begingroup$ @NuclearHoagie "you can't sign to someone not looking at you, as a simple example" don't spoken languages have similar limitation, e.g., can't speak to someone behind glass wall, while sign language can. If you want to make a case against "any system of communication with a sufficiently large expressive capacity is more-or-less equivalent" probably you can compare spoken languages, for example some languages are more practical to talk about the distinct nuances of green, another maybe more practical for technological discussion, etc. $\endgroup$
    – justhalf
    Oct 7, 2022 at 7:12
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    $\begingroup$ @NuclearHoagie: This sort of suggests that any system of communication with a sufficiently large expressive capacity is more-or-less equivalent [...]. Yes: that's a deep and empirically well-supported fact about natural languages. You can read it as a converse of the Sapir–Whorf hypothesis. $\endgroup$
    – Vectornaut
    Oct 9, 2022 at 0:25

The short answer is: absolutely. For a longer answer it's important to call out that there's likely some unnamed bias in the "as advanced as..." standard, because "advanced" is not a technically specific term.

What would likely happen in the event of a society who, for whatever reason, had no audio-channel means of communication and their primary language was hand-sign, is a divergence of technological development. If you're needing your hands free to speak, things like automation or alternatives to hand-tools become VERY much more important and likely a hard-focus for that society. Communication at long distance will look very different, with SMS or telepresence being likely initial targets.

The advancement of technology is an emergent property of knowledge and communication. But there would be technological sectors that simply held little value for a culture that did not make noises to communicate with one another and so would be considered "primative" or "underdeveloped" by societies for whom such technologies held value.

And on the flipside, there would be technologies that such societies would develop as part of their natural inquiry which would have voice-speaking societies scratching their heads and saying, "They do what with WHAT? HOW?!"


They aren't limited to sign language

Frame challenge: Homo Mutus only lacks a voice box - that does not mean their only option is sign language. Although they could develop a society with only sign language, and probably would use it for their primary language, you have more storytelling options than that.

Sign language has the drawback that you can't yell to get someone's attention, and you can't communicate around corners. Homo Mutus people wouldn't exactly need to do those things, but they would certainly be nice to have, particularly in combat. They aren't deaf, they just lack a voice box.

Therefore, although sign language would be their primary mode of communication, they might use musical instruments to communicate over long distances or when the other party can't be seen.

Horns or drums might be simple, loud, practical options for long-distance communication, particularly in wartime or in the wilderness. (You don't need a voicebox to blow air into a horn; you just need the ability to control your exhalation). They could develop a musical language based on one or more of these instruments, supplementing their sign language. It could be like Morse code. Indoors, people might use it to call people to dinner by clacking a spoon on the wall. Outdoors, they would use proper instruments to call over long distances.

(By the way, what about whistling? You don't need a voice box to whistle, just control over your breathing, tongue, and lips, but it does seem to break the spirit of "Homo Mutus." Perhaps you can just say that they don't have the necessary fine control of their lips and tongue.)

  • $\begingroup$ The problem is that you can't blow a horn while holding a gun, hammering a forge, etc. $\endgroup$
    – RonJohn
    Oct 8, 2022 at 2:39
  • $\begingroup$ @RonJohn You can't use sign language while your hands are occupied, either. Also if they feel the need, perhaps they could design an instrument that is held up to the mouth by a stand, so it's hands-free. Consider the harmonica neck holder, which lets you play a harmonica hands-free. $\endgroup$
    – causative
    Oct 8, 2022 at 5:34
  • $\begingroup$ So much "recency bias" going on here... Go back 80,000 years (because if this species evolved 100,000 years ago and survived to this day, they'd by definition have also been around 80,000 years ago...) to the paleolithic era: it's absurd to think they'll have harmonicas and harmonica neck holders. $\endgroup$
    – RonJohn
    Oct 8, 2022 at 15:25
  • $\begingroup$ @RonJohn And did I say they would have harmonicas? No I didn't. Harmonica neck holders on the other hand are pretty simple technology, all it really takes is some shaped sticks. There is no reason the instrument held to the mouth must be a harmonica; it could be a horn. (Not that harmonicas require modern technology; they don't. They're just a box with a reed in it and a bunch of holes.) $\endgroup$
    – causative
    Oct 8, 2022 at 16:48

Of course. In addition to sign language, they could also be able to communicate the same ideas we can using instrument base languages like talking drums. Talking drums can allow someone to communicate with someone else over four to five miles away according to the book Interfaces of the Word: Studies in the Evolution of Consciousness and Culture by Walter Ong. There is also Silbo Gomero, a whistling language where people communicate simply by whistling in different pitches and tones at different intervals. People have been able to use it to communicate over distances of four to five kilometers, so even without spoken language, your version of humanity would still be able to communicate for long distances, especially since whistling would not require a voice box: just the ability to blow and properly pucker your lips.


Devil's Advocate answer: No. (Or, only with written language also.)

A lot of answers here are saying yes, and for good reasons. However, to play Devil's Advocate, I believe there's also a compelling case for non-vocal human beings never achieving the same level of advancement.

Sign languages can be equally complex as spoken languages, and the barriers of use in certain contexts are likely not sufficiently high as to make it practically inferior to spoken language. However, spoken language was not by itself what catapulted human beings to the top of the evolutionary ladder. Written language may have been more important.

You could definitely get to the Agricultural Revolution without written language, but I'm not convinced you could get much further than that. You mention Homo mutus uses "sign languages and written languages", and I think it's worth focusing on this second component. Sign language itself is difficult to write down (though there are ways). You could perhaps end up with an ideographic language representing ideas with characters, but language (even written language) is cognitively understood through phonological encoding (or in Deaf people, through an analogous process, which is why finger spelling is important) and thus must fundamentally be structured in a phonological hierarchy.

Keep in mind that what makes human beings advanced is our cooperation. We use stories and collective fictions to surpass the Dunbar Number (the 150 people in a tribe that you can know simply through everyday interactions). We're capable of cooperating with and trusting other human beings in neighboring villages, simply because they share the same beliefs with us and can communicate productively. This is very important. Equally important as shared belief systems is a use of writing far more mundane, and that's record keeping. It's easy to overlook the effect that record keeping has had on civilization, but no sufficiently large and complex political body could exist without the capacity to keep and preserve detailed records. Record keeping, resource tabulation, mathematics, and so forth, are of the utmost importance. An economic system cannot exist without a written language capable of keeping records. Yes, a barter system works to a certain degree, but is impractical when scaling upwards. Small groups can survive with barter alone. For entire civilizations, it is generally beyond impractical. (Barley coin--despite not being a coin--was decently successful in Babylon, and other cultures have used rice and perishable goods as currency, but even this requires systems of measurement and records of transactions and monetary equivalencies.)

In summary, it isn't spoken/signed communication that's important for advanced civilizations (which is not to say it's trivial), it's written communication and record keeping.

  • $\begingroup$ All proposed writing systems for sign languages (Sutton SignWriting, HamNoSys, Stokoe Notation, ASLWrite, ...) are in fact phonemic. $\endgroup$
    – TRiG
    Mar 23, 2023 at 22:44
  • $\begingroup$ That's a good point, but as far as I know those are post hoc writing systems. My guess is that if you were developing a sign language completely in the absence of spoken language, the writing system would skew toward non-phonemic. Morphemes would still remain useful, but I'm not sure that phonemes would. $\endgroup$
    – 40EridaniB
    Apr 9, 2023 at 16:45
  • $\begingroup$ Is there any writing system which isn't "post hoc"? $\endgroup$
    – TRiG
    Apr 10, 2023 at 21:04
  • $\begingroup$ Looking into this some more, you're absolutely right. All written languages must be post hoc because it seems there is no way of learning a purely written language (by itself) within the required developmental timespan, and moreover, written languages are (rather incredibly) understood cognitively through phonological encoding and thus necessarily must be phonological. I'll edit my answer. $\endgroup$
    – 40EridaniB
    May 6, 2023 at 17:15

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