This article was downloaded by: [Selcuk Universitesi] On: 13 January 2015, At: 14:34 Publisher: Taylor & Francis Informa Ltd Registered in England and Wales Registered Number: 1072954 Registered office: Mortimer House, 37-41 Mortimer Street, London W1T 3JH, UK International Journal of Human-Computer Interaction Publication details, including instructions for authors and subscription information: http://www.tandfonline.com/loi/hihc20 An Approach to Design Virtual Keyboards for Text Composition in Indian Languages Debasis Samanta a , Sayan Sarcar a & Soumalya Ghosh a a Indian Institute of Technology Kharagpur , Kharagpur , India Accepted author version posted online: 19 Sep 2012.Published online: 10 Jun 2013. To cite this article: Debasis Samanta , Sayan Sarcar & Soumalya Ghosh (2013) An Approach to Design Virtual Keyboards for Text Composition in Indian Languages, International Journal of Human-Computer Interaction, 29:8, 516-540, DOI: 10.1080/10447318.2012.728483 To link to this article: http://dx.doi.org/10.1080/10447318.2012.728483 PLEASE SCROLL DOWN FOR ARTICLE Taylor & Francis makes every effort to ensure the accuracy of all the information (the “Content”) contained in the publications on our platform. However, Taylor & Francis, our agents, and our licensors make no representations or warranties whatsoever as to the accuracy, completeness, or suitability for any purpose of the Content. Any opinions and views expressed in this publication are the opinions and views of the authors, and are not the views of or endorsed by Taylor & Francis. The accuracy of the Content should not be relied upon and should be independently verified with primary sources of information. 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Journal of Human–Computer Interaction, 29: 516–540, 2013 Copyright © Taylor & Francis Group, LLC ISSN: 1044-7318 print / 1532-7590 online DOI: 10.1080/10447318.2012.728483 An Approach to Design Virtual Keyboards for Text Composition in Indian Languages Debasis Samanta, Sayan Sarcar, and Soumalya Ghosh Indian Institute of Technology Kharagpur, Kharagpur, India They also reported that approximately 247 billion e-mails were Of late there has been significant development in Information sent worldwide each day in 2009. It is predicted that this fig- and Communication Technology (ICT), which offers interaction ure will almost double to 507 billion messages per day by 2013, with computing systems in a large scale. Text input mechanisms with the expected increment of users up to 1.9 billion (Releases, in users’ own languages are necessary for bringing the ICT advan- tages to the English illiterates. QWERTY keyboard, however, which 2009). In spite of the speedy growth of the text composition was designed for text entry in English, is not as suitable for text task, text composition rate is still too low. Text composition rate composition in other languages. As an alternative, researchers of expert typist users in the English language is 30 to 45 words advocate virtual keyboards in users’ mother languages. This arti- per minute (Brown, 1988), whereas for computer users having cle proposes an approach to designing virtual keyboards suitable basic knowledge it is only 5 to 10 words per minute (Fazly, for text entry in Indian languages. Composition of texts in Indian languages using virtual keyboards needs special attention due to 2002). The result becomes even lower in the case of an Indian the presence of large character sets, complex characters, inflexions, language like Hindi, Bengali, or Telugu. Therefore, it is nec- and so on. First, we examine the suitability of existing design prin- essary to support a text composition task in digital devices and ciples in developing virtual keyboards in Indian languages. Then help the users to perform tasks with better text entry methodolo- we propose a virtual keyboard layout suitable for efficient text gies in coming years. As an example, in English, a speech-based entry in Indian languages. We have tested our approach with the three most spoken languages in India, namely, Bengali, Hindi, and text composition system augmented with error minimization Telugu. Performance of the keyboards have been evaluated, and support has already been developed (Fischer, Price, & Sears, the evaluation substantiates that proposed design achieves on aver- 2006). A virtual keyboard is one of the solutions for addressing age 21.3% higher text entry rather than with conventional virtual the requirement of providing a better text composition rate. It is keyboards. The proposed approach, in fact, provides a solution to a soft keyboard that imitates the QWERTY hardware keyboard deal with complexity in Indian languages and can be extended to many other languages in the world. ambiance for a text entry system. In addition, the configuration of a virtual keyboard can be changed effortlessly at any point of time, are which is not easily possible on a QWERTY key- board. Also, virtual keyboards are beneficial because they can 1. INTRODUCTION be implemented in any type of digital device with any language Presently, people all around the world communicate using specification. In these devices, a text entry task is not possi- Downloaded by [Selcuk Universitesi] at 14:34 13 January 2015 handheld digital devices like cell phones and PDAs as well as ble through a conventional hardware keyboard due to mobility desktop PCs and laptops. Recent statistics reveals that nearly restriction, size factor, and so on. 1 billion text messages are sent each day (MacKenzie & Tanaka- These days, many applications in a wide range of digital Ishii, 2007). In an Indian context, message composition draws devices like cell phones (Sears & Zha, 2003), iPhones, digital more attention, where 220 million mobile subscribers sent TVs (Perrinet et al., 2011), and so on, use a virtual keyboard to more than a billion text messages in 2007–2008 (Newslog, enter data or text. The text entry performance of a virtual key- 2010). According to the report of Technology Market Research board depends on its design. The English-language-compatible (Reports, 2009), there were 1.4 billion e-mail users in 2009. virtual keyboards are based on some design strategies like the special arrangement of keys, a minimum distance between This work was carried out under a project sponsored by Department character pairs, and so on. A well-known key arrangement is of Information Technology, Government of India. We express our known to be in QWERTY (Chubon & Hester, 1988, Sarcar sincere thanks to all participants for their painstaking efforts in the et al., 2010) fashion. The principle behind designing another evaluation of keyboards. Address correspondence to Sayan Sarcar, School of Information popular keyboard layout called FITALY (Fitaly, 2009) is the Technology, Indian Institute of Technology Kharagpur, Takshashila character frequency of the English alphabet, which decides Building, Kharagpur, West Bengal 721302, India. E-mail: mail- the position of different character keys on the virtual key- [email protected] board. In FITALY, the frequently occurring keys are placed in 516 DESIGN OF VIRTUAL KEYBOARDS 517 the central position. The Space character, which is accessed solution space and appears to be a difficult problem in most, has two buttons. MacKenzie and Zhang (1999a) pro- the case of Indian languages. posed an optimized keyboard arrangement called OPTI.This layout requires four keys for Space, and other keys are spa- A few virtual keyboards exist to compose texts in Indian lan- tially arranged based on their digraph probabilities (Jelinek, guages such as Google (Google, 2009), Microsoft (Microsoft, 1990). The characters having superior digraph probabilities can 2009), gate2home (gate2home, 2010), LooKeys (LooKeys, be arranged in the middle of the keyboard, and inferior proba- 2009), Lipik (Lipik, 2007), MyLanguage (MyLanguage, 2008), bility valued character pairs are placed at the outer part of the Avro (OmicronLab, 2010), and so on. These keyboards follow keyboard. Zhai, Hunter, and Smith (2000) used physical laws to alphabetical ordering or Inscript (Indian script) mapping tech- develop virtual keyboards. One of the approaches used mechan- nique (Technology Development for Indian Languages, 1986). ical simulation of a mess of springs of Hooke’s Law (n.d.), Moreover, the existing virtual keyboards occupy a larger screen which tries to minimize the distance between character pairs. area. Hooke’s keyboard (Zhai et al., 2000) uses digraph probabilities We have addressed the issues of designing virtual keyboards between two characters of English alphabets and arranges the for Indian languages in this article. We propose to retain good keys having higher value side by side followed by less proba- design principles of a English language-based virtual keyboard ble characters to the other vacant space. In another approach, in our design. This guides us to put the merits of existing virtual developers