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Saral: Devanagari Text input system in Mobile phones Anshuman Kumar IDC, IIT Bombay

Mumbai 400076, India anshuman.3@gmail.com

Hemruchi Shah IDC, IIT Bombay

Mumbai 400076, India hemruchi@gmail.com

Anirudha Joshi IDC, IIT Bombay

Mumbai 400076, India anirudha@iitb.ac.in

ABSTRACT Mobile phone subscriptions in India crossed the 415 million mark in May 2009. Yet, the unavailability of a usable Indian language text input systems in mobile phones prevent people from using simple applications like the SMS and phonebook in their own language. This paper proposes “Saral”, a new onscreen Devanagari text input system for mobile phones. It follows the structure of the Devanagari script and provides a simple interface by grouping consonants, vowels and punctuations. When a consonant is pressed, the vowel group is replaced by a group of corresponding vowel modifiers. Audio feedback and colour coding helps people with poor vision. The non-touch screen version of the application uses only five keys of the keypad for input. In usability tests, Saral was found to be more learnable and easier to use compared to currently available solutions.

Author Keywords Indian language computing, text input devices, digital divide, Devanagari text input, mobile phone, Indian Languages text input.

ACM Classification Keywords H5.m. Information interfaces and presentation: Interface Design, User Centered Design, Screen Design

INTRODUCTION Contrary to popular perceptions a large majority of Indians can’t communicate in English. For these users, language is a big barrier for technology adoption. 2001 Census data indicates that 45% (468M) people in India are illiterate and about 76% (771 M) people have not studied beyond the primary school [2]. In most Indian language schools, English is taught only after the primary classes. English is not the most preferred language even among the more educated – the circulation of daily English periodicals is only 19% compared to 42% of Hindi periodicals [3].

Tele-density in India has reached 39% [1] with increasing number of new connections coming from non-English

speaking users. However, the current telecom growth comes mainly from voice communication. The other advantages of information and communication technologies remain unavailable to many. Non-voice mobile phone applications such as SMS, phonebooks, emails, chat, blogging etc. are almost entirely used in English [5]. For example, even non-English TV shows call for SMS feedback in English. This points to an eminent need for a text input system in Indian languages.

CHALLENGES IN DEVANAGARI TEXT INPUT The typing experience on mobile phones in any language, involves a complex combination of mental and physical coordination. This is even more complex for Devanagari input. Devanagari is an abiguda script which is used for writing several Indian languages like Sanskrit, Hindi, and Marathi etc. Devanagari has 13 commonly used vowels, 34 commonly used consonants and additional diacritic marks (fig 1). A typical character in Devanagari is formed by a combination of a consonant and a vowel modifier. For example . Other combinations such as stand-alone vowels ( ...), consonant + consonant + vowel ( ) and consonant + vowel + vowel ( ) are also commonly used [5]. In theory, Devanagari has infinite number of combinations, but in practice about 1100 glyphs are commonly used [4].

Fig 1. The ‘Devanagari Varnamala’- showing frequently used vowels, their mantras, consonants, conjuncts & graphic signs

There are various issues related to Devanagari text input generally including complex script system, large number of glyphs, differences in methods of writing and typing and large number of characters [5]. This affects learnability,

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ease of use and speed of typing. On mobile phones, these issues are even more enhanced because of the small screen and keypad and users’ less attention span than on desktop computers.

AVAILABLE INPUT METHODS ON MOBILE PHONES Currently there are three different methods of text input in Devanagari: Multi-tapping, two-level coding and phonetic mapping.

Multi-tapping The most commonly used text entry method is the one where multiple characters are mapped to the same key and the user presses that key to cycle through the letters until the desired one appears on the screen. This is not a suitable solution for Devanagari due to the large number of characters in the script. As a result, as many as 12 characters have been mapped on some keys. For the Roman script, at the most 4 letters are mapped on one key – p, q, r and s on 7 and w, x, y and z on 9 and these are already hard to use. An important reason why these systems are not usable is that people forget the sequence of the characters and often overshoot. “While frantically pressing a key again and again, one ends up skipping the desired alphabet. One fails to quickly recognize it due to its small size and ambiguous shape. It is also quite tiring to keep gazing at the location where alphabets are speedily changing. Naturally you cannot recognize them quickly, and then you have start typing all over again” [6]. Currently, Nokia and LG phones use this method.

Two-level Coding In this system, the hierarchical grouping of letters in Devanagari is leveraged by assigning a two digit code to each letter. The first digit represents the group and the second represents the individual letter in the group. On pressing a key, the group associated to it is displayed on the screen. While the user is in this mode, the same keys are associated with a letter in the group. For example, the group

is represented by key 1 and when it is pressed, the screen displays . Now if key 1 is pressed again, gets typed. In this method only 2 clicks are required for every letter. One problem with this system is modality – users take some time to get used to the operation and keep making errors from time to time. Secondly, while some letters are naturally grouped (e.g. consonants), grouping of all letters is not equally intuitive. Currently, Samsung phones use this method for text input.

Phonetic mapping to Roman script In this method Devanagari alphabets are phonetically grouping on to the keypad to their closest Roman characters. For example, (ba, bha) are mapped to the Roman B (key 2) and (ka, kha) are mapped to K (key 5). The main issue with this system is that there is no predictable mapping between Devanagari and Roman characters. In some cases, up to four Devanagari characters need to be mapped on one Roman character (e.g. t

), while in other cases there are

ambiguities arising out of different pronunciations of the same Roman character in different contexts (based on English pronunciation). Thirdly, the user needs to multi-tap through several unwanted groups before entering the wanted group. For example, to select a , which is mapped to B (key 2), the user needs to tap through all the letters mapped to A (which happen to be 11 in number, given the variety of ways in which A is pronounced in English). This adds to the complexity. Currently, Sony Ericsson phones use this method.

Figure 2. Various Devanagari text input methods for mobile

phones. 1- Multitapping, 2- two level coding, 3- Phonetic mapping to Roman script

USER STUDY The project started with a heuristic analysis of the current phone input methods by 8 experts from fields of design, engineering, arts and cognitive psychology. The group performed various activities like typing an SMS, adding contact in Hindi using the three different text input systems. Also, a series of contextual inquires were done with 8 Hindi-speaking users from three different cities. These users belonged to middle class families. 3 of them had studied till primary school while others were educated with different levels of proficiency at English. Six had rarely typed in an Indian language on a mobile phone while the other typed in Hindi regularly (5-10 times a week). These users were given the task to save contacts in Hindi with increasing order of complexity of the contact names. They were also asked ot write the following sentence on the mobile-phone:

The studies generated several user needs and design ideas including:

• The varnamala could be clearly represented on the keypad / screen.

• The diacritic of halant should be highlighted • The number of characters mapped on the keypad could

be reduced

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PROPOSED SOLUTION

Fig 3. The design of Saral in an 8x7 grid. The blue group are the vowels and the yellow tones are the consonants. The last column contains space bar, backspace and diacritic marks.

The dark brown cells are the commonly used conjuncts.

Based on the insights from the user study we decided to choose the solution of on-screen interface (rather than keypad-based input). In our design, a majority of Devanagari letters are displayed in an 8x7 grid. The letters are grouped as vowels (blue cells in figure 3), consonants (yellow tones in columns 3-7 in figure 3) and other diacritic marks (column 8 in figure 3). The four frequently used conjuncts are displayed as a small group at bottom right. This layout closely resembles the Devanagari structure. The layout and selection rules were iteratively improved through several rounds of user feedback.

At any time, one cell of the grid is highlighted. On non-touch-screen phones the interaction involves only 5 keys – the four arrow keys of the keypad are used to navigate through the grid and the central key inputs the highlighted letter. The navigation in the grid is looped – navigating out of the edge from one side brings the highlight in from the opposite edge. In the worst case, the maximum number of keystrokes required to move between two characters is 7.

Initially, the first two columns display the standalone vowels (figure 3). These can be used to input any consonant or standalone vowel e.g. etc. When a consonant is typed, the first two columns change to the vowel modifiers (figure 4a). These can be used to input a consonant + vowel combination e.g. (figure 4b). These remain available as long as a valid vowel modifier can be typed. To input a consonant + consonant + vowel combination, the halant diacritic mark needs to be inserted between the two

consonants. For example .

Fig 4. Typing consonant + vowel combination in Saral

The different groups of letters are colour coded to make it easier for the user with poor vision to differentiate between them. There is also a voice feedback in terms of the pronunciation of the letters when they come into focus.

USABIILITY EVALUATION Saral and existing Devanagari input systems in Nokia, Samsung and Sony Ericsson mobile phones were evaluated by a group of students in a usability evaluation course. Hindi-speaking users with educational background between 7th to 10th standards were recruited. These had been using a mobile phone from 6 months to 2 years, but had never typed Hindi on a phone before. The goal of the evaluation was to compare the three different text input systems and Saral with respect to learnability, error free use and ease for beginners. For the evaluation a flash prototype of Saral was deployed on Nokia 6300.

Five users were recruited for each text input method (5x4). All users were exposed to a common test protocol and setup. To begin with a 5-minute orientation of the phone model and its native text input method was given to each user. The orientation included a demonstration of typing a few words in Hindi. After this, the user was shown cards each with a Hindi word printed on it and was asked to type it on the phone. In all, there were 18 words arranged in an increasing order of difficulty. The number and sequence of words was the same for all users.

Fig 5. 18 Word cards ranging from simple to complex given to

the users one at a time, for text input

The user was encouraged to first type each word without help. If he could figure out how to type the word on his

own, it was considered to be ‘successful without help’. If the user needed help to type a word, it was considered ‘successful with help’. If the user gave up or could not type with help, it was counted as an unsuccessful attempt.

Findings Table 1 summarises the average number of words successfully typed by users without and with help. Saral had the highest number of words successfully typed without help per user (53%) and the total number of words typed successfully per user (98%). The difference between Saral and Samsung was significant beyond α = 0.01 (one tailed). The differences between Saral and other phones were more significant.

Table 2 summarises the same data for the last (and hardest) 6 words that involved a conjunct. Here again, Saral had the highest number of words successfully typed without help per user (23%) and the total number of words typed successfully per user (93%). For the six hardest words, the difference between Saral and Samsung was significant beyond α = 0.03 (one tailed).

It was found that after learning how to type a word, the next similar word was typed faster in case of Saral. Time taken to complete tasks was less as the user did not have to worry about finding the alphabets. Speed and accuracy data has not been statistically mentioned as ‘n’ is small, which makes the data insignificant .

Saral Samsung Nokia Sony Ericsson

Successful without help

9.6 (53%)

7.8 (43%)

8.0 (44%)

3.4 (19%)

Successful with help

8.0 (44%)

8.2 (46%)

2.4 (13%)

4.2 (23%)

Total successfully typed words

17.6 (98%)

16.0 (89%)

10.4 (58%)

7.6 (42%)

Table 1. Average number of words successfully typed by users without and with help, out of total 18 words. n=5 per phone.

Saral Samsung Nokia Sony Ericson

Successful without help

1.4 (23%)

0.8 (13%)

0.8 (13%)

0.6 (10%)

Successful with help

4.2 (70%)

3.8 (63%)

1.0 (17%)

0.6 (10%)

Total successfully typed words

5.6 (93%)

4.6 (77%)

1.8 (30%)

1.2 (20%)

Table 2. Average number of words successfully typed by users without and with help, for the hardest 6 words. n=5 per phone.

CONCLUSION We can conclude that Saral is easier for the beginner compared to the existing input systems. Grouped display of consonants, vowels and contextual vowel modifiers and the audio support helped in the learning and eventually speed and error free use in Saral. Making options visible is important in inputting complex scripts. It is also important to tailor-make the input system for the structure of the script rather than using multi-tap as a standard method for all scripts. After Saral, the two-level coding system used in Samsung phones seems to be doing this the best.

During the evaluation, we noticed a design flaw in Saral – a word that has a standalone vowel following a consonant without a vowel modifier can’t be typed in the current prototype. (For example the word can’t be typed in the current design.) We have devised a work around for this problem, but it has not yet been evaluated at this time.

ACKNOWLEDGMENTS We thank Kumar Ahir, Riyaz Sheikh, Shwetha, Nikhil Welanakar and Kirti Kantikar for their help in prototyping the product. We thank Nokia for part-funding our protyping effort. We also thank Prof. Uday Athvankar and Prof. Milind Malshe for their valuable feedback and support during the project. We thank participants of our heuristic evaluations and students of course IN 604 for the year 2008 for their help.

REFERENCES 1. Telecom Regulatory Authority Of India, (Press Release

No 56/2009) www.trai.gov.in/WriteReadData/trai/upload/PressReleases/689/pr19june09no56.pdf, 20 June, 2009

2. Census of India, Edu. lev. by age and sex for population age 7 and above www.censusindia.net/results/C_series/C_series_pdf/c8_india.pdf. 20 June, 2009

3. Registrar of Newspapers of India, General Review https://rni.nic.in/pii.asp, March 2006 data, 20 June, 2009

4. Naik B.S, Typography of Devanagari vol-1, 1971, 175- 176

5. Joshi, A., Ganu, A., Chand, A., Parmar, V., Mathur, G., Keylekh: a keyboard for Text entry in Indic Scripts CHI 2004, April 24-29, 2004, 3-4

6. Katre, S.Dinesh. Position Paper on “Cross-cultural Usability Issues of Bilingual (Hindi & English) Mobile Phones” Indo-Danish HCI Research Symposium 2006, 10-11