Natural Language Processing

Neelnavo KarAlex Huntress-Reeve

Robert HuangDennis Li

What is Natural Language Processing?

• NLP is an interdisciplinary field that uses computational methods to:o Investigate the properties of written human language and

model the cognitive mechanisms underlying the understanding and production of written language.

o Develop novel practical applications involving the intelligent processing of written human language by computer.

What is NLP? (cont.)

• NLP plays a big part in Machine learning techniques:o automating the construction and adaptation of machine

dictionarieso modeling human agents' desires and beliefs

essential component of NLP closer to AI

• We will focus on two main types of NLP:o Human-Computer Dialogue Systemso Machine Translation

Human-Computer Dialogue Systems

• Usually with the computer modelling a human dialogue participant

• Will be able: o To converse in similar linguistic styleo Discuss the topico Hopefully teach

Current Capabilities of Dialogue Systems

• Simple voice communication with machineso Personal computerso Interactive answering machineso Voice dialing of mobile telephoneso Vehicle systemso Can access online as well as stored information

• Currently working to improve

The Future of H-C Dialogue Systems

• The final end result of human computer dialogue systems:o Seamless spoken interaction between a computer and a human

• This would be a major component of making an AI that can pass the Turing Test

• Be able to have a computer function as a teacher

Human Computer Dialogue in Fiction

• Halo's Cortana AIo Made from models of a real human braino Made to run the shipo Made very human conversations

• Ender's Game series: Janeo Made from "philotic connection"o Human conversation

Problems of Human-Computer Dialogue

• At the moment, most common computer dialogue systems (call systems, chatter bots, etc.) cannot handle arbitrary inputo In many cases, the computer can only respond to "expected"

speecho Call systems often compensate with "Sorry, I didn't get that,"

when something unexpected is said.

Problems of Human-Computer Dialogue

• Computers need to be able to learn and process colloquial speech• Needed to understand informal speakers:

o Understanding varied responses for call systems o Accounting for variations in spoken numbers

• Processing colloquialisms is also necessary for seamless dialogue, where the computer must avoid sounding too formalo John Connor: "No, no, no, no. You gotta listen to the way

people talk. You don't say 'affirmative,' or [stuff] like that. You say 'no problemo.' "

Successes of Human-Computer Dialogue

• So far, human-computer dialogue has been most successful in applications where information about a specific topic is sought from the computer.o Electronic calling systems: company-specifico Travel agents: specific to an airline or destination

• However, more complex systems of human-computer dialogue have been produced which can interpret more varied input.o Physics tutoring system (ITSPOKE) which can analyze and

explain errors in the response to a physics problem.o Allows for more complex input than "Yes," "No," or "Flight

UA-93"• These still cannot compare to true human-human dialogue.

Machine Translation

• Important for:o accessing information in a foreign languageo communication with speakers of other languages

• The majority of documents on the world wide web are in languages other than English

Statistical Translation

• Rule based• Works relatively well with large sets of data• Used probability to translate text• Natural translations• Google

Example Based Translation

• Converts "parallel" lines of text between language• Only accurate for simple lines• Minimal pairs are easy• Analogy based

Paraphrasing

• Takes words and makes them simpler automatically• For example in Spanish conjugated words like usado may be

changed to usar

Future of Machine Translation

• Goal:o Aim to be able to flawlessly translate languages

• Link Human-Computer Dialogue and Machine Translation• Have someone be able to talk in one language to a computer,

translate for another person• Translated Video Chat

Machine Translation in Fiction

• Star Wars: C-3P0o Interpretero Could hear and translate alien languageso Final goal of machine translation

• Star Trek: Universal Translatoro Computer can seamlessly translate alien languages

Problems

• Works well only with predictable texts.• Doesn't work well with domains where people want

translation the most: o spontaneous conversationso in persono on the telephoneo and on the Internet.

Problems

• Computers can't deal with ambiguity, syntactic irregularity, multiple word meanings and the influence of context.

Time flies like an arrow.Fruit flies like a banana.

• Accurate translation requires an understanding of the text, situation, and a lot of facts about the world in general.

The box is in the pen. 

Problems

• The sign is describing a restaurant (the Chinese text, 餐厅 , means "dining hall"). 

• In the process of making the sign, the producers tried to translate Chinese text into English with a machine translation system, but the software didn't work, producing the error message, 

    "Translation Server Error." • The software's user didn't

know English and thought the error message was the translation.

Successes

• Product knowledge bases need to be translated into multiple languages

• Hiring a large multilingual support staff is expensive• Machine translation is cheaper and accurate with

predictable texts.• Microsoft, Autodesk, Symantec, and Intel use it.

o Makes customers happyo Still readable though slightly chunkier than human

translations