TechWire

A Sinhala touch keyboard for mobile devices

Reproduced with permission from http://zen.lk/2013/05/21/a-sinhala-touch-keyboard-for-mobile-devices/

Google Transliteration for Sinhala has probably done more to encourage active participation of Sinhala speakers on the Internet than any other technology or initiative. Using a simple English character based transliteration scheme that most Sinhala speakers are familiar with, it enables the average user to input Sinhala text into a computer at moderate speed without any knowledge of local layouts such asWijesekara.

However, things are not quite so simple when it comes to touch-based mobile devices. While placing a standard QWERTY keyboard on a mobile touchscreen is in itself an awkward attempt to use a layout meant for one type of device in another, using the same thing for transliterating a different language is doubly awkward. No solution exists in any of the dominant mobile platforms — Android, iOS or Windows Phone.

An innovative and widely used touchscreen keyboard scheme known as Swype may point the way. As many users would tell you, Swype allows you to drag your finger across the letters that form your word in one smooth motion. A prediction algorithm generates the word when you lift your finger off the screen. While this is a good scheme for any language, the nature of the Sinhala alphabet affords special advantages when using it.

sinhala_keyboard_2

While the Sinhala language has a large number of characters (without even counting combined ones), the most basic characters are:

ක ග ත ද න ප ය ර ල ව ස ශ හ ට ජ ච බ ම අ ඉ ඊ උ එ ඔ

When we consider ‘mahaprana’, ‘sanyaka’ and ‘murdhaja’ as alternate forms and combine these characters with the various ‘pillas’, almost all Sinhalese characters may be formed.

Features of this keyboard are as follows:

  1. The user may swipe his finger from one character to another to form words.

  2. Swiping over a ‘pilla’ key immediately after a basic character causes that character to be modified by the selected pilla.

  3. Tracing a small circle over a ‘pilla’ key causes it to become its long version.

  4. Swiping over the ‘shift’ key immediately after a basic character causes that character to become its mahaprana or murdhaja version (the software determines which, based on the base character).

  5. Swiping over the ‘binduwa’ key causes the preceding character to become its sanyaka version. When the key is tapped in isolation, it produces a ‘binduwa’ character.

  6. If a predictive dictionary is present, the user need not always be explicit about long pillas, mahapranas and especially murdhajas. The software will be able to pick out the correct form from the dictionary, given an approximation.

  7. Punctuation characters and numerals may be typed by a press-and-hold action (similar to the Swype keyboard).

  8. There are no dedicated characters for the vowels. Using a pilla character at the beginning of a word produces the corresponding vowel.

Rationales:

  1. Unlike English speakers and the QWERTY layout, Sinhala speakers have not become accustomed to the Wijesekara or any other Sinhala layout. This will allow them to quickly become accustomed to a new one.

  2. The layout can cut the number of strokes required to produce a word by about one third to one half, depending on the frequency of ‘pillas’. For example, the word ‘ලංකාව’ requires six swipes (or seven taps) on QWERTY. In this layout, it requires only four swipes.

  3. Reaching for keys on the higher rows naturally results in keys on the lower rows getting obscured by the user’s finger. Therefore the number of rows must be kept to a minimum and difficult-to-memorize keys should not be placed on the lower rows.

  4. The number of columns must be kept to a minimum so as to not make keys too small. Sinhala characters require more display space than English ones.

Improvements:

  1. The consonants here are placed in near-alphabetic order. However, the most optimal placement can be determined by statistical analysis of a large enough sample of frequently used Sinhala words and phrases. For example, ස, ය, ල, ම should probably be in higher rows than they are in this crude layout.

  2. The placements of the enter, backspace, comma and full stop keys may require rethinking.

  3. Infrequently used keys such as ‘rakaranshaya’ and ‘binduwa’ may be converted to shift functions to make space for ශ (which is currently considered a shifted ස) and more punctuation

      

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Hasitha Liyanage

I am a software engineer with an interest in science, technology and process improvement.

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