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Many linguists believe the same set of principles act on sub-word units, a theory called Distributed Morphology or DM[0] "'Syntactic Hierarchical Structure All

Many linguists believe the same set of principles act on sub-word units, a theory called Distributed Morphology or DM[0] "'Syntactic Hierarchical Structure All the Way Down' entails that elements within syntax and within morphology enter into the same types of constituent structures (such as can be diagrammed through binary branching trees). DM is piece-based in the sense that the elements of both syntax and of morphology are understood as discrete instead of as (the results of) morphophonological processes."[1] So a rather simplified way to think about it is that each word is a little mini-tree and Merge operations create a branching structure between its constituent parts. Each of those words is then part of the larger sentence-level tree. The important this is that Merge is acting on the units at both levels. Similarly, Merge can act on structures that are the output of previous Merges, allowing you to have a verb, in a particular conjugation (it's sub-word structure), that selects for a particular type of supra-word structure (a tree) that's headed by a noun with some set of features, eg a particular case. Another point that is kind of alluded to in the article is that you can create movement from one part of a tree to another with Merge. In previous theories of syntax, there always needed to be both something like Merge and a special "move" operation. But Merge simplifies things quite a bit in that regard. [0]https://en.wikipedia.org/wiki/Distributed_morphology https://en.wikipedia.org/wiki/Distributed_morphology [1] https://www.ling.upenn.edu/~rnoyer/dm/#how%20DM%20is%20different https://www.ling.upenn.edu/~rnoyer/dm/#how%20DM%20is%20diffe...

schoen 7y ago
Whoa, that's amazing! Can you explain a little more about how something like an agreement rule would be analyzed in this framework? I suppose I didn't quite understand your "that selects for a particular type of super-word structure (a tree) that's headed by a noun with some set of features". Is this sort of akin to a type system in programming? Like the verb is only willing to bind with a subject noun phrase whose head has a particular feature?
- eindiran 7y ago
  In this framework, you can think about a morpheme as being a tuple of features. Like you said, it is sort of akin to a type system, where passing the wrong type to a function won't work. A morpheme will select for a feature or set of features from whatever its merged with, and won't merge with something it doesn't agree with. I think using a language which doesn't care much about word order will be illustrative here, so let's use Latin: puella vidit canem The girl sees the dog We can break this down into: puell - a vid - et can - em girl - NOM.S.FEM sees - S.3 dog - ACC.S.FEM So 'puella' is the tuple of features [+NOM, +S, +FEM], 'videt' is [+PRES, +ACTIVE, +S, +3], etc. Here, we want to do a Merge with 'puella' and 'videt': we say that 'puella' selects for the features +NOM, +3, +S (nominative, third person, and singular) in its verb, but doesn't care about the others. It can still agree with its verb if the verb is passive or in the past tense. But if a verb is conjugated in a way that violates the features it selects for (eg the verb is conjugated as first person plural), 'puella' won't merge with it. As you said, a phrase level structure will have the features of its constituent parts bubble up to it. So once we've done the first Merge with 'puella' and 'videt', our structure is now selecting for a noun phrase that has the feature +ACC. Because 'canem' meets this requirement, we can get the final Merge necessary for our finished sentence. { { puella, videt }, canem } Note that this account still works if we change the order of the sentence to any configuration, we just need to reorder the merges.
  - jaclaz 7y ago
    Yep, but, as soon as you exit very simple phrases subject/action/object, the approach may become complex to apply in practice, a couple (known) latin (tricky) examples (JFYI): mala mala mala sunt bona Soli soli soli
    - eindiran 7y ago
      Unfortunately that's true, which is why linguistics is a field of study with its own journals, rather than something that can be summarized neatly in the space of an HN comment :P This model really can account for quite complex language data though. For example, check out this account of auxiliary verbs in Basque: https://www.academia.edu/3112898/A_Distributed_Morphology_Analysis_of_Present_Tense_Auxiliaries_in_Zamudio_Basque https://www.academia.edu/3112898/A_Distributed_Morphology_An... Speaking to your examples: "mala mala mala sunt bona" isn't particularly difficult to analyze this way, you just need to realize that the "mala"s are different words (kind of like the famous English "Buffalo buffalo Buffalo buffalo buffalo buffalo Buffalo buffalo" sentence). If I remember the proverb correctly, it means "apples (mala) are good (sunt bona) for a painful jaw (mala mala)". You need an analysis that allows adjectives to Merge with nouns iff they match case, gender and number, so that allows us to create a noun phrase "mala mala" in the instrumental ablative. Then you need a way to have the case, gender and number of subject bubble to the top of the phrase it will make with an auxiliary so that the adjective after the auxiliary is feature restricted to that case, gender and number. Once the elements of the auxiliary verb phrase have Merged, you get: {{ mala, sunt }, bona } Finally you have a rule that allows auxiliary verb phrases to Merge with noun phrases headed by an ablative. If you want the first "mala" to be the subject, then re-Merge it with the whole sentence so far, which in effect moves it to the top of the tree, leaving a trace in its original position. I'm not sure what the second example means. My best guess is that it's the dative singular of 'sol', a matching masculine dative singular of 'solus' and a genitive singular of 'solum', so something like "for the only sun of the land". If that's correct, you need our previously used rule for Merging adjectives iff they match the noun in case, gender and number. Then you can add an additional rule that genitive nouns can be Merged with noun phrases (without any feature selection needing to take place) to form a new noun phrase. Hopefully that shows that Merge and feature selection as mechanisms can be used outside of toy models, to actually account for real data.
ajuc 7y ago
This is still wrong. Nouns and verbs can change irregularly depending on each other. It's like people look only at their own language and try to pretend that same structure must be universal.
- schoen 7y ago
  From the examples that I saw in this thread and on Wikipedia, it seems like this framework does try to account for this complexity by positing more specific rules that require those changes to happen in order for the Merge to be allowed. Since I just heard about this for the first time, I'm not sure I can justify the claim that it succeeds for every aspect of every language, but it looks like the people promoting this approach are aware of quite a bit of the possible complexity of language. Can you suggest a more example of a linguistic phenomenon that you think this framework can't deal with?

schoen 7y ago

Whoa, that's amazing! Can you explain a little more about how something like an agreement rule would be analyzed in this framework? I suppose I didn't quite understand your "that selects for a particular type of super-word structure (a tree) that's headed by a noun with some set of features". Is this sort of akin to a type system in programming? Like the verb is only willing to bind with a subject noun phrase whose head has a particular feature?

eindiran 7y ago
In this framework, you can think about a morpheme as being a tuple of features. Like you said, it is sort of akin to a type system, where passing the wrong type to a function won't work. A morpheme will select for a feature or set of features from whatever its merged with, and won't merge with something it doesn't agree with. I think using a language which doesn't care much about word order will be illustrative here, so let's use Latin: puella vidit canem The girl sees the dog We can break this down into: puell - a vid - et can - em girl - NOM.S.FEM sees - S.3 dog - ACC.S.FEM So 'puella' is the tuple of features [+NOM, +S, +FEM], 'videt' is [+PRES, +ACTIVE, +S, +3], etc. Here, we want to do a Merge with 'puella' and 'videt': we say that 'puella' selects for the features +NOM, +3, +S (nominative, third person, and singular) in its verb, but doesn't care about the others. It can still agree with its verb if the verb is passive or in the past tense. But if a verb is conjugated in a way that violates the features it selects for (eg the verb is conjugated as first person plural), 'puella' won't merge with it. As you said, a phrase level structure will have the features of its constituent parts bubble up to it. So once we've done the first Merge with 'puella' and 'videt', our structure is now selecting for a noun phrase that has the feature +ACC. Because 'canem' meets this requirement, we can get the final Merge necessary for our finished sentence. { { puella, videt }, canem } Note that this account still works if we change the order of the sentence to any configuration, we just need to reorder the merges.
- jaclaz 7y ago
  Yep, but, as soon as you exit very simple phrases subject/action/object, the approach may become complex to apply in practice, a couple (known) latin (tricky) examples (JFYI): mala mala mala sunt bona Soli soli soli
  - eindiran 7y ago
    Unfortunately that's true, which is why linguistics is a field of study with its own journals, rather than something that can be summarized neatly in the space of an HN comment :P This model really can account for quite complex language data though. For example, check out this account of auxiliary verbs in Basque: https://www.academia.edu/3112898/A_Distributed_Morphology_Analysis_of_Present_Tense_Auxiliaries_in_Zamudio_Basque https://www.academia.edu/3112898/A_Distributed_Morphology_An... Speaking to your examples: "mala mala mala sunt bona" isn't particularly difficult to analyze this way, you just need to realize that the "mala"s are different words (kind of like the famous English "Buffalo buffalo Buffalo buffalo buffalo buffalo Buffalo buffalo" sentence). If I remember the proverb correctly, it means "apples (mala) are good (sunt bona) for a painful jaw (mala mala)". You need an analysis that allows adjectives to Merge with nouns iff they match case, gender and number, so that allows us to create a noun phrase "mala mala" in the instrumental ablative. Then you need a way to have the case, gender and number of subject bubble to the top of the phrase it will make with an auxiliary so that the adjective after the auxiliary is feature restricted to that case, gender and number. Once the elements of the auxiliary verb phrase have Merged, you get: {{ mala, sunt }, bona } Finally you have a rule that allows auxiliary verb phrases to Merge with noun phrases headed by an ablative. If you want the first "mala" to be the subject, then re-Merge it with the whole sentence so far, which in effect moves it to the top of the tree, leaving a trace in its original position. I'm not sure what the second example means. My best guess is that it's the dative singular of 'sol', a matching masculine dative singular of 'solus' and a genitive singular of 'solum', so something like "for the only sun of the land". If that's correct, you need our previously used rule for Merging adjectives iff they match the noun in case, gender and number. Then you can add an additional rule that genitive nouns can be Merged with noun phrases (without any feature selection needing to take place) to form a new noun phrase. Hopefully that shows that Merge and feature selection as mechanisms can be used outside of toy models, to actually account for real data.

ajuc 7y ago

This is still wrong. Nouns and verbs can change irregularly depending on each other. It's like people look only at their own language and try to pretend that same structure must be universal.

schoen 7y ago
From the examples that I saw in this thread and on Wikipedia, it seems like this framework does try to account for this complexity by positing more specific rules that require those changes to happen in order for the Merge to be allowed. Since I just heard about this for the first time, I'm not sure I can justify the claim that it succeeds for every aspect of every language, but it looks like the people promoting this approach are aware of quite a bit of the possible complexity of language. Can you suggest a more example of a linguistic phenomenon that you think this framework can't deal with?