Xiaojun Wan
Automatic Text Simplification
Peking University
automatic text simplification special task texttotext generation converts text another text easier read understand underlying meaning information remains text simplification system usually replaces difficult unknown phrases simpler equivalents transforms long syntactically complex sentences shorter less complex ones example siddharthan 2006 first sentence contains two relative clauses one conjoined verb phrase text simplified version also contributing firmness copper analyst noted report chicago purchasing agents precedes full purchasing agents report due today gives indication full report might hold also contributing firmness copper analyst noted report chicago purchasing agents chicago report precedes full purchasing agents report chicago report gives indication full report might hold full report due todayresearch automatic text simplification started 20 years ago become important area natural language processing nlp attracted much attention recent years text simplification facilitates adaptation textual material also helps make texts easier process use thus making accessible information reality however easy task involves lexical syntactic semantic issues possesses interesting challengesthis book written horacio saggion covers key issues text simplification including automatic readability assessment lexical simplification syntactic simplification machine learningbased simplification applications text simplification moreover describes several typical full text simplification systems introduces text simplification evaluation techniques offers available resources research development book written elegant way enjoyed reading consists nine chapters chapter focused single specific topic text simplification readers easily choose one several almost selfcontained chapters covering topics interested inchapter 1 briefly introduces automatic text simplification need technology introduces two different text simplification tasks address different subproblems lexical simplification syntactic simplification text simplification tools useful large range users reading difficulties eg people aphasia autism spectrum disorder tools used create adapted versions texts specific populations appreciate text simplification task promising nlp technology social goodchapter 2 provides overview topic readability assessment relevant many approaches automatic text simplification readability assessment techniques used determine complexity given text thus compare outputs different text simplification systems trivial automatically assess readability level text chapter several classical readability formulas presented discussed including flesch reading ease score fleschkincaid readability formula fog readability score smog readability score robust methods relying rich syntactic semantic features described along typical classification regression algorithms eg svm knn logistic regression used methodschapter 3 covers techniques addressing lexical simplification problem replacing words phrases simpler equivalents introduces first approach lexical simplification based wordnet carroll et al 1998 spanish lexical simplification system based word sense disambiguation approaches based comparable corpora distributional lexical semantics described followed description numerical expression simplification system chapter also covers relevant evaluation challenges complex word identification lexical simplification provide benchmark data sets future researchchapter 4 covers techniques address syntactic simplification problem simplifying syntactic structure sentences phrases note chapter introduces rulebased approaches require large annotated corpora describes first syntactic simplification approach targeting constructions relative clauses appositions chandrasekar doran srinivas 1996 approach using typed dependencies followed full rulebased simplification system implemented pipeline four main components approaches relying information extraction generation also outlined chapter contains examples rules helpful readers understandingchapter 5 covers techniques learn simplification corpora chapter first introduces methods cast text simplification monolingual machine translation specia 2010 surveys methods use statistical syntactictree translation process also surveys optimization techniques rule application recent techniques incorporate semantic information simplification problem growth computing power data scale learningbased simplification methods become prevalent neural network models especially sequencetosequence models successfully applied text simplification readers encouraged read recent papers supplement chapterchapter 6 presents three fully fledged text simplification systems different readerships languages pset english carroll et al 1998 simplext spanish saggion et al 2011 porsimples brazilian portuguese alusio gasperin 2010 systems designed specific target populations people aphasia people low literacy people cognitive disabilities details systems described clearly benefit practitioners build text simplification systemschapter 7 introduces various applications automatic text simplification chapter first introduces applications text simplification specific target populations covered chapter 6 describes use text simplification facilitate nlp tasks including parsing information extraction text summarization personally like see usefulness text simplification nlp tasks also expect see extensive use text simplification nlp fieldchapter 8 covers two important topics text simplificationthe available data sets experimentation current evaluation techniques chapter introduces lexical resources english nonenglish corpora text simplification useful building testing text simplification models systems chapter provides automatic evaluation metrics methods including machine learningbased ones note automatic evaluation accurate enough human evaluation usually reliable automatic evaluation text simplification develop accurate automatic evaluation metrics techniques research direction areachapter 9 concludes overview field text simplification critical view current stateoftheart approachesin summary saggions book provides comprehensive indepth introduction automatic text simplification covering methodologies resources text simplification worth noting materials reading end chapter also valuable resources book recommended researchers students practitioners work area text simplification also wide range readers interested area still long way go interesting area look forward seeing new approaches resources text simplification