Design And Implementation Of An English Spell And Grammar Checking System

People produce texts, and therefore the use of computers rises more and more. Thegrammatical correctness is often very important and thus spell and grammarcheckers are applied. Most nowadays grammar checkers are based on rules, butoften they do not work as properly as the users want. To counteract this problem, anew approach on using rules as a basis is advanced. This work introduces such aspell and grammar checkers: design and implementation of an English spell andgrammar checking system.New fields of spell and grammar checking arise through more power, storagecapabilities and speed of today's computer systems. Statistical data is freelyavailable through the Internet, e.g. through search engines, online newspapers,digital texts, and papers. These basic principles lead to a new idea about spell andgrammar checking.The aim of this thesis is to develop a spell and grammar checker system for theEnglish language. Although all major open source word processors offer spell andgrammar checking, a few of them offer a complete spell and grammar checkerfeature. Such a feature is not available as a separate free program either. This workis presented to fill this gap. Thus, the result of this thesis can be used both as a stand-alone spell and grammar checker and as an integrated part of a word processor.The spell and grammar checker system described in this thesis takes a text andreturns a list of possible suggestions for every detected error. To detect errors, eachword of the text is assigned its part-of-speech tag. Then the text is matched with theentire checker's predefned error rules. If a rule matches, the text is supposed tocontain an error at the position of the match. The rules describe errors as patterns ofwords and part-of-speech tags. Each rule also includes an explanation of the error,which is shown to the user.The system is based on software that has been developed by the author. Boththe designed spell and grammar checker and the part-of-speech tagger, which itrequires, are implemented in C language. The rule system is designed to be morepowerful so that it can detect all cases of a single rule. The integration into wordprocessors will be improved so that errors can be detected on-the-fy, i.e. during textinput. The developed checker for both spell and grammar errors is evaluated usingdifferent judgment methods. Precision and Recall are two important percentagevalues for evaluating the presented programming. In addition, the results of theproposed checker are compared to other commercial tools such as Microsoft Word.Evaluation results prove that the developed spell and grammar checkerapproach provides a robust observer for the English language. The reliability of theproposed method is very important, i.e. it is mandatory to provide enough data ingood quality to find all grammatical errors.Moreover, beside the rule-based method for detecting grammatical errors, anew method is applied to ensure these results. This method is the statistical-basedmethod. It depends on comparing the input text to a massive collection of storeddata to detect the errors. Then, to propose a correction, it uses the same stored datato offer the nearest matching with the given input.The thesis is organized in five chapters in which the researcher covers thebasic principles of English language programing. It introduces the aim of the thesisin a very systematic way to the design and implementation methodology of spell andgrammar checking systems for the ill-written sentences of the English language. Thethesis is well organized and easy to read. Several topics are discussed and presentedin a very original way as a result of the wide research performed by the author.