(Construction) Grammar does not Suffice for NLU Jerome Feldman, ICSI & UC Berkeley Natural Language Understanding (NLU) is a manifest goal for applied linguistics, but its theoretical importance is not as obvious. Integrated form-meaning pairs comprise the crux of Construction Grammar, but what is meaning? Decades of work at ICSI/UCB has established that embodied semantics (ECG) is necessary, but we also know that it is not sufficient. Language is inherently contextual and underspecified. An isolated grammar theory or program can only provide schematic analyses (SemSpecs in ECG) that are inadequate for full NLU. https://github.com/icsi-berkeley/ecg_homepage/wiki 1
Natural Language Understanding • Natural Language Processing (NLP) is the overall category – Search, Machine Translation, Sentiment Analysis, etc. • . Natural Language Understanding (NLU) ~ action without human intervention – Google Search vs. Google Car • Why NLU might be of interest to ICCG – Greater outside interest, support – CxG seems necessary for compositional approach – Full path understanding redefines many fundamental issues • Current Mainstream Approaches – Templates: Siri, Cortana, Google, Alexa (next slide) – Machine Learning • Natural Language Generation adds more complications – Habitability Problem – FCG – Luc Steels Slide 2
Amazon Alexa Skills ~ Templates developer.amazon.com/alexa-skills-kit GetHoroscope what is the horoscope for { Sign} GetHoroscope what will be the horoscope for { Sign} be on {Date} GetHoroscope get me my horoscope … MatchSign do {FirstSign} and {Second Sign } get along MatchSign what is the relationship between {FirstSign} and {Second Sign } 3
The Winograd Challenge http://www.cs.nyu.edu/faculty/davise/papers/WinogradSchemas/WS.html All Pronoun Referent Resolution 1. The city councilmen refused the demonstrators a permit because they advocated / feared violence. 3. The trophy doesn't fit into the brown suitcase because it is too large/small. 5. Joan made sure to thank Susan for all the help she had received/given 7. Paul tried to call George on the phone, but he wasn't successful/ available. 9. The lawyer asked the witness a question, but he was reluctant to repeat/ answer it. 11. The delivery truck zoomed by the school bus because it was going so fast/slow. 15. The man couldn't lift his son because he was so weak/heavy 4
ECG2 - NLU Beyond the 1980s 1. Much more computation 2. NLP technology 3. Construction Grammar: form-meaning pairs Conceptual compositionality + Idioms, etc. 4. Cognitive Linguistics: Conceptual primitives, Metaphor, etc. ECG = Embodied Construction Grammar; 6 uses of formalism 5. Constrained Best Fit : Analysis, Simulation, Learning Analysis uses Bayesian (form, meaning and context) best fit 6. Under-specification: Meaning involves context, goals, etc. SemSpec = Semantic/Simulation Specification 7. Simulation Semantics: Meaning as action/simulation 8. CPRM= Coordinated Probabilistic Relational Models; Petri Nets ++ Action formalism works as a generative model 9. Domain Semantics; Need rich semantics on the Action side 10. General NLU front end: Modest effort to link to a new Action side Slide 5
Language as Logic Yet every sentence is not a proposition; only such are propositions that have in them truth or falsity. Thus a prayer is a sentence, but it is neither true nor false. Let us therefore dismiss all other types of sentences but the proposition, for this last concerns our present inquiry, whereas the investigation of others belongs rather to the study of rhetoric or poetry. Aristotle (De Interpretatione 17a1-8).
Functionalism In fact, the belief that neurophysiology is even relevant to the functioning of the mind is just a hypothesis. Who knows if we’re looking at the right aspects of the brain at all. Maybe there are other aspects of the brain that nobody has even dreamt of looking at yet. That’s often happened in the history of science. When people say that the mental is just the neurophysiological at a higher level, they’re being radically unscientific. We know a lot about the mental from a scientific point of view. We have explanatory theories that account for a lot of things. The belief that neurophysiology is implicated in these things could be true, but we have very little evidence for it. So, it’s just a kind of hope; look around and you see neurons: maybe they’re implicated. Noam Chomsky 1993, p.85
Embodiment Of all of these fields, the learning of languages would be the most impressive, since it is the most human of these activities. This field, however, seems to depend rather too much on the sense organs and locomotion to be feasible. Alan Turing ( Intelligent Machines ,1948) < Continuity Principle of Darwin, American Pragmatists >
Actionability in Integrated Cognitive Science 1. All living things act ; acting is what living things do. 2. Natural selection constrains the fitness ( utility ) of these actions. 3. Actionability is an agent's assessment of the expected utility of an external or internal action. 4. Volition is the key concept; agents perform volitional as well as automatic actions 5. This defines, but does claim to solve, actionability as a integrating issue for Cognitive Science. 6. No answers are suggested for hard mind-brain problems like subjective agency. 7. Actionability calculation often involves simulation of action and its consequences. Feldman JA(2016)Actionability and Simulation: No Representation without Communication. Front.Psychol.7:1204. doi:10.3389/fpsyg.2016.01204 Slide 9
Active representations • Many inferences about actions derive from what we know about executing them • X-net representation based on stochastic Petri nets captures dynamic, parameterized nature of actions • Used for acting, recognition, planning, and language walker at goal Walking: bound to a specific walker with a direction or goal energy consumes resources (e.g., energy) may have termination condition (e.g., walker at goal ) walker =Harry ongoing, iterative action goal =home
“Indian government stumbling in implementing Liberalization Policy.”
How do we specify an event? Formalized event schema FRAME PARAMETER Actor Preconditions Theme Effects hasFrame hasParameter Instrument Resources - In, Out EVENT Patient Inputs Outputs Duration Grounding ISA Time, Location RELATION(E1,E2) Subevent COMPOSITE Enable/Disable CONSTRUCT EVENT Suspend/Resume CONSTRUAL Sequence Abort/Terminate Phase ( enable, start, Concurrent/Conc. Sync Cancel/Stop finish, ongoing, cancel ) Choose/Alternative Mutually Exclusive Manner ( scales, rate, path ) Iterate/RepeatUntil(while) Coordinate/Synch Zoom ( expand, collapse ) If-then-Else/Conditional • Key elements – preconditions, resources, effects, sub-events – evoked by frames (alternatively: predicates, words) • Contrast with Event Recognition/Extraction, other NLP work 12
Embodied Construction Grammar • Embodied representations – active perceptual and motor schemas (image schemas, x-schemas, frames, etc.) – situational and discourse context • Construction Grammar – Linguistic units pair form and meaning / function – Meaning pole based on (conceptual) Schemas . – Both constituency and (lexical) dependencies used. • Constraint-based – Based on feature unification (as in LFG, HPSG) – Best fit: Diverse factors flexibly interact.
Ideas from Cognitive Linguistics • Embodied Semantics (Lakoff, Langacker, Sweetser, Talmy) • Radial categories (Rosch 1973, 1978; Lakoff 1985) – mother: birth / adoptive / surrogate / genetic, … • Radical Construction Grammar ( Croft 2001) – Reference, Modification, (Predication -> Event Description) • Metaphor and metonymy (Lakoff & Johnson 1980, …) – ARGUMENT IS WAR, MORE IS UP – The ham sandwich wants his check. • Mental spaces (Fauconnier 1994) – The girl with blue eyes in the painting really has green eyes. • Conceptual blending (Fauconnier & Turner 2002, inter alia) – workaholic, information highway, fake guns – “Does the name Pavlov ring a bell?”
Conceptual Compositionality Ontology Fragment (type motion sub process) (type create sub process cause) (type move sub motion) (type walk sub motion) (type enter sub motion) (type exit sub motion) (type run sub motion) (type drive sub motion)
Semantic Specification “the man built the house”
ECG Workbench ECG Workbench: ● Based on Eclipse ● Takes advantage of and fully integrates with Eclipse RCP (Rich Client Platform) ● Makes it easy to enter, edit and check consistency of ECG grammars ● Can analyze text licensed by the grammar, producing a SemSpec (Sem antic Spec ification) ● Available at: https://github.com/icsi-berkeley/ecg_homepage
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Embodied Construction Grammar: ECG • ECG serves : 1. as a technical tool for linguistic analysis 2. to specify shared grammar, conceptual conventions of a linguistic community 3. as a computer specification for implementing linguistic theories 4. as a representation for models and theories of language acquisition 5. as a front-end module for applied language-understanding tasks 6. as a high-level functional description for biological and behavioral experiments
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