◎ JADH2016

Sep 12-14, 2016 The University of Tokyo

Characteristics of a Japanese Typeface for Dyslexic Readers
Xinru Zhu (University of Tokyo)
Introduction

Evidence shows that 3%–5% of the population have developmental dyslexia[*1] in Japan [1], and providing them with assistive environment is essential. While it is held that typefaces have impacts on dyslexic readers [2], Japanese typefaces for dyslexic readers have not been created, mainly because it is not easy to provide a special typeface that fits everyone with dyslexia.

Against this backdrop, we are developing (i) a Japanese typeface for people with developmental dyslexia and (ii) a typeface customization system, targeting the situation in which people read articles or textbooks.

This poster presents the Japanese typeface we designed for dyslexic readers. In designing the typeface, we analysed Latin typefaces designed for dyslexic readers and extracted characteristics they have, defined desiderata for Japanese typefaces for dyslexic readers by mapping these characteristics to Japanese char- acters, and created a Japanese typeface for dyslexic readers by applying these desiderata for dyslexic readers. We elaborate on each of these steps in our pre- sentation.

Characteristics of Latin Typefaces for Dyslexic Readers

There are several Latin typefaces specially designed for dyslexic people, includ- ing Dyslexie, OpenDyslexic, Lexie Readable, Sylexiad and Read Regular. We examined the characteristics of Dyslexie, OpenDyslexic and Lexie Readable for the reason that they are relatively widely used and evaluated in several studies. Studies show that typefaces have significant impacts on readers with dyslexia [3] and with specially designed typefaces, dyslexic readers either was able to read with less errors [4, 5, 6] or preferred the specially designed typefaces compared to normal typefaces [7].

In order to identify the characteristics of the special designed typefaces, we measured[*2] the letterforms of 3 special typefaces and 6 normal sans-serif type- faces[*3] and summarized them parametrically based on PANOSE classification[*4], numerically based on the sizes and ratios of the typefaces and visually based on the direct comparison. The font data was converted to the Unified Font Object[*5] from commonly used format to make it easy to access to coordinates of points constructing glyphs from Python scripts. The methods adopted ensure repro- ducibility and objectivity of the study.

Table 1 describes PANOSE numbers and the characteristics of typefaces they show. Table 2 and Table 3 show the PANOSE values of Arial and Dyslexie and Figure 1 and Figure 2 shows the average sizes and ratios of the typefaces. Figure 3 is a part of the visual comparison of Arial and Dyslexie in the same size, in which blue letters are in Arial and red ones are in Dyslexie.

The results show that Latin typefaces for dyslexic readers have the following characteristics.

  1. The characteristics of the entire typeface:
    (a) Rounded sans-serif typefaces,
    (b) Larger letters in the same size,
    (c) Larger height/width ratios,
    (d) Standard x-heights,
    (e) Longer descenders and ascenders,
    (f) Bolder strokes,
    (g) Contrast in stroke width.
  2. The characteristics related to identifying similar letters:
    (a) Similar letters slanted or rotated to opposite directions,
    (b) Uppercase “I, J” and numeric character “1” with serifs,
    (c) Numeric character “0” with a dot inside the counter,
    (d) Asymmetry letterforms of lowercase “p, q” and “b, d”,
    (e) Handwritten style of lowercase “a, y” and numeric character “9”,
    (f) Larger counter sizes of lowercase “a, c, e, s”.

Table 1: PANOSE Number and Characteristics of Typefaces

Table 2: PANOSE Values of Arial

Table 3: PANOSE Values of Dyslexie

Figure 1: Sizes of the Typefaces

Desiderata for Japanese Typefaces for Dyslexic Readers

A Japanese font set includes Latin characters, Kana characters and Kanji char- acters, not mentioning punctuation marks and other symbols, in which Latin characters and Kana characters are phonograms while Kanji characters are lo- gograms [9]. Neuropsychological studies indicate that phonograms and logograms are processed differently in human brains [10], which makes it reasonable to dis- cuss possible characteristics of Kana characters and Kanji characters separately.

Figure 2: Ratios of the Typefaces

Since Kana characters are phonograms same as Latin characters, the hypoth- esis is that some characteristics of the Latin typefaces for dyslexic readers can be applied directly to the entire Kana typeface. It is indicated that forms of some Kana characters are similar to one another which leads to confusion during char- acter recognition [11]. The characteristics related to identifying similar letters hence can be applied to those characters. The possible characteristics of Kana typefaces are listed below.

  1. The characteristics of the entire typeface:
    (a) Maru gothic typefaces[*6],
    (b) Larger characters in the same size,
    (c) Larger height/width ratios,
    (d) Bolder strokes,
    (e) Contrast in stroke width,
    (f) Larger counters.
  2. The characteristics related to identifying similar characters:
    (a) Hiragana characters “ら, う”, “る, ろ”, “は, ほ” [11], “い, こ”, “め, ぬ”, and “へ, く” [12] modified distinguishable,
    (b) Katakana characters “ス, ヌ”, “セ, ヤ”, “ウ, ワ”, “ワ, フ”, “ワ, サ”, “ソ, ン” and “ユ, エ” [11] modified distinguishable.

As for Kanji characters, there are two possible strategies. First, Kanji charac- ters can be treated in the similar way as Kana characters since the visual aspects of Kanji characters are considered to play an important role in character recog- nition [13]. The second strategy is to emphasize the structure of Kanji characters inside the typeface according to widely adopted assistive practices.

Figure 3: Visual Comparison of Arial and Dyslexie

A Prototype of Japanese Typefaces for Dyslexic Readers

We selected all the Hiragana and Katakana characters and 80 Kanji characters instructed to be taught in the first grade in elementary schools by the Ministry of Education, Culture, Sports, Science and Technology of Japan to be included in the first prototype of the typeface. Since each Kanji character is constructed with certain strokes, the idea is to start from the characters with fewer strokes and expand gradually. Kanji characters will be expanded to 2136 characters of Jo¯ yo¯ Kanji, commonly used Kanji characters announced by the Government of Japan, in the final design.

The first prototype of the Japanese typefaces for dyslexic readers is modi- fied based on an open source Japanese typeface. We converted it to the Unified Font Object and applied the possible characteristics summarized above by run- ning Python scripts on the data of glyphs. The results of modification will be demonstrated in the poster. The prototype will be put on evaluation in cooperation with dyslexic readers in further studies and the results will be reflected to the characteristics of the Japanese typefaces for dyslexic readers.

Note

[*1] Developmental dyslexia is defined as “a specific learning disability that is neurobiological in origin. It is characterized by difficulties with accurate and/or fluent word recognition and by poor spelling and decoding abilities” according to the International Dyslexia Association.

[*2] Measurements and modification of typefaces were conducted using the programming lan- guage Python and RoboFont, a Python based font editor (http://doc.robofont.com/).

[*3] They are Arial, Calibri, Verdana, Trebuchet, Comic Sans, and Sassoon Primary. These type- faces are selected based on the recommendation of the British Dyslexia Association.

[*4] PANOSE is “a system for describing characteristics of Latin fonts that is based on calculable quantities” [8].

[*5] The Unified Font Object is a human readable XML format for storing font data. http:// unifiedfontobject.org/.

[*6] Maru gothic is Japanese counterpart of rounded sans-serif.


References

[1] Tomonori Karita, Satoshi Sakai, Rumi Hirabayashi, and Kenryu Nakamura. Trends in Japanese Developmental Dyslexia Research [in Japanese]. Journal of Developmental Disorder of Speech, Language and Hearing, 8:31–45, 2010.

[2] Shinji Iizuka. A Classification of Assistive Technologies for Reading Disor- der Based on the Process of Language Understanding [in Japanese]. IEICE Technical Report. Welfare Information Technology, 106(612):43–48, 2007.

[3] Luz Rello and Ricardo Baeza-Yates. Good Fonts for Dyslexia. In Proceed- ings of the 15th International ACM SIGACCESS Conference on Computers and Accessibility, page 14. ACM, 2013.

[4] Maya Grigorovich-Barsky. The Effects of Fonts on Reading Performance for Those with Dyslexia: A Quasi-Experimental Study, 2013.

[5] Tineke Pijpker. Reading Performance of Dyslexics with a Special Font and a Col- ored Background. Master thesis, University of Twente, 2013.

[6] Renske De Leeuw. Special Font For Dyslexia? Master thesis, University of Twente, 2010.

[7] Robert Alan Hillier. A Typeface for the Adult Dyslexic Reader. PhD thesis, Anglia Ruskin University, 2006.

[8] Yannis Haralambous. Fonts & Encodings. O’Reilly Media, 2007.

[9] Florian Coulmas. Writing Systems : An Introduction to Their Linguistic Analy- sis. Cambridge University Press, 2003.

[10] Makoto Iwata and Mitsuru Kawamura. Neurogrammatology [in Japanese]. Igaku-Shoin, 2007.

[11] Tatsuya Matsubara and Yoshiro Kobayashi. A Study on Legibility of Kana- letters [in Japanese]. The Japanese Journal of Psychology, 37(6):359–363, 1967.

[12] Nobuko Ikeda. Research on Educational Support of Japanese Language Learners with Developmental Dyslexia [in Japanese]. Journal of the Study of Japanese Language Education Practice, (2):1–15, 2015.

[13] Cecilia W. P. Li-Tsang, Agnes S. K. Wong, Linda F. L. Tse, Hebe Y. H. Lam, Viola H. L. Pang, Cathy Y. F. Kwok, and Maggie W. S. Lin. The Effect of a Visual Memory Training Program on Chinese Handwriting Performance of Primary School Students with Dyslexia in Hong Kong. Open Journal of Therapy and Rehabilitation, (3):146–158, 2015.