Phrasal Stress Or Modal Ambiguity

Dogs must be carried Mark Liberman has an abnormally interesting post at Language Log. He shows us these two signs. The first sign unpacks as, “If you happen to have a dog with you, you must carry that dog when riding this escalator. Otherwise, you don’t need to carry a dog to ride the escalator.” It does not unpack as “You can’t ride this escalator unless you are caring a dog.”
The second one unpacks as, “You are required to wear safety shoes beyond this sign. If you’re not wearing safety shoes you can’t enter.” It does not unpack as, “If you happen to have safety shoes with you, you must wear them beyond this sign. Otherwise you don’t need to wear safety shoes.”
But how do we know which way to disambiguate these signs? They are syntactically the same. Liberman points to differences in phrasal stress. In the first sign the subject, “dogs,” is stressed and in the second the verb, “must be,” is stressed. However, I don’t think there would necessary be any differences in intonation or lengthening in our reading of these sign.
Safety shoes must be worn
Liberman also suggests that some might see a difference in modality between “must be” in the first sign and “must be” in the second sign. But on what basis would we recognize that modality or assign phrasal stress? As far as I can see only non-linguistic cultural markers (and rather difficult to define cultural markers at that) allow us to disambiguate the two messages.
I can’t think of a case in an ancient text were this kind of phrasal stress or modal ambiguity is a worry? Are there any? How would we identify them?

5 thoughts on “Phrasal Stress Or Modal Ambiguity”

  1. I think the missing ‘cultural markers’ are actually missing ‘linguistic terms’ – a common practic in the modern world: the writers assume the readers will bring this cultural awareness with them and use it to complete the sentences.
    1st sign: ‘In the rare event that you are travelling with a dog and must use an automatic walkway, etc’ : dogs must be carried. So ‘Dogs’ tends to be stressed.
    2nd sign: Safety shoes must be worn: “because it’s a requirement of working in this area”. Wearing shoes is relatively normal – being required to wear special shoes is not, unless you’re working in a special area and now it’s no longer a case of a personal choice: it’s a requirement. Thus, the stress on ‘must’.
    The Language Log is reminding me of some old logic problems that took their stand on semantic wrangling heh heh! Perhaps it’s being needlessly complicated and the key is merely the missing linguistic/cultural information?
    I imagine a similar effect might be gotten by taking some Levitical laws, abridging them, and then posting them in areas where they are appropriate (rather than have one big scroll)- signs posted near the altar, signs posted near the Tent of Meeting, etc.
    I think you’re probably correct in thinking that ancient texts have examples of the problems listed at the Language Log – that cultural/linguistic divide is one of the reasons to study the languages, right? I’m not sure if one could replicate the modern trend of abbreviating signs, though. Maybe a close approximation?
    Interesting post!

  2. I’d didn’t mean that the cultural markers were missing but that they were extra-linguistic (at least in the narrow sense). I think we are in agreement on this. Ancient epigraphic material is often highly abbreviated.

  3. Um, why are people going up escalators with dogs? I’m a dog owner myself. That’s a disaster waiting to happen. :O But then, if one is fumbling blindly through life reading signs, “misreading modalities” and such, instead of using one’s common sense (if any), perhaps these impending accidents are a good thing. Evolution is super.

  4. All in context (cultural or otherwise). You see a sign; based on the context you find it, you’ll decide on which interpretation is most likely. The words are just added to help you narrow the probabilities down.
    You’re driving in a wooded area. You see a sign which shows only a deer leaping to the left. With no words, you’ll probably correctly (and without much thinking) understand it’s warning you deer are nearby (and thus, you might want to be careful driving). Change the deer on the sign to a cow and stick that in Chino, you get a similar interpretation.
    Now, same road, but this time it is a sign with just a T-Rex lumbering to the left. The context that the sign is found doesn’t help much, but you might have possibilities such as a Cretaceous Period fossil dig sight is nearby. Change the setting of the sign to Pasadena, now you might ponder the possibility of a museum be located nearby, or maybe a store with dinosaur themed items to sell. If text is added, even extremely terse phrasing, this would quickly help remove a number of possibilities so that you settle on the appropriate one.
    NOW, if I were to see the escalator sign you have here located in a Hilton hotel, but no text had been added to the sign, I high ranking possibility that would have come to my mind is that this was Paris Hilton crossing zone, beware because she might be on her way to get more money from daddy… but that’s just me.

  5. Busi,
    My underling concern is how we deal with such things (or even identify such things) where we don’t know or are not sure of the larger context.
    By the way, I tried to send you a copy of my pisser paper but my email was bounced as spam. I tried both my own SMTP server and Yahoo Mail with and without attachments. I not sure what is going on but if you have a suggestion on how to get around whatever the problem is, I’m still willing to send you a copy of the paper.

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