Learning advantage

Named after its inventor Louis Braille in 19th century France, Braille is a tactile representation of alphabetic symbols using six dots to represent each letter.

The Braille system commonly used in English-speaking countries may not be suitable for tonal languages spoken in Asia, Africa and the Americas, where over 1.5 billion people use these languages.

China is among the countries requiring an improved Braille system distinct from the standard one. Mandarin Chinese is a tonal language, as the pitch or the tone in which the word is spoken contributes to its meaning.

Similar to many tonal languages worldwide, Mandarin conveys specific meanings but the original Braille system fails to represent its tones.

Braille relies on pinyin, the system for writing Chinese words using the Roman alphabet. A loss of meaning takes place with the conversion from visually based graphic characters to auditory-based phonetic Braille.

Standard Braille's shortcomings may hamper visually impaired students in acquiring knowledge because the absence of tones can result in numerous ambiguities, Zhong said.

The inherent learning potential of visually impaired children is no different from that of other children, according to Zhong, but various factors may impede their learning ability and cause them to lag behind others.

In extensive reading, visually impaired individuals often rely on contextual cues to infer word meanings, but this form of inference may be inadequate in learning new knowledge.

"When students come across unfamiliar or new words, grasping their meanings becomes challenging. This lead to numerous difficulties in the learning process," Zhong said.

The traditional Braille system without tone notation was established in 1953. Since then, researchers have continually explored methods to integrate tones into Braille.

In 1988, Huang Nai, a pioneer in China's education for the visually impaired, introduced a two-cell Braille system to address the shortcomings of non-tonal Braille.

"The new system successfully implemented tone notation in two cells, but it overthrew the old Braille system. This required visually impaired individuals to learn an entirely new language, causing them to undergo the pains of Braille reform," Zhong said.

The two-cell system faced many challenges and after a five-year trial period, its use was discontinued.

"In the span of these 20 years dedicated to developing tonal Braille, we've essentially circled back to our starting point," Zhong said.

The primary challenge in incorporating tones into Braille is to strike a balance between tone accuracy and conserving Braille cells. Any alterations to the Braille system must consider the reading habits of the visually impaired, Zhong said.

"To add tones isn't inherently complex; by introducing an additional six-dot Braille cell to denote tone after the initial and final consonant cells of each character, this can be achieved. However, such an approach significantly increases cell amount and drastically slows down reading speed," he said.

From 2007, Zhong started to explore ways to add tones into the Braille system without overturning the original system. In 2009, Zhong's project was launched and received national social science funding.

"Our new version should not overturn the original system. We should consider blind people's reading habits," he said.

Initially, Zhong planned to create a homophone corpus of Mandarin to annotate words in Braille. However, he later abandoned the strategy as it would pose a significant burden of memorization on visually impaired people.

To strike a balance between tone accuracy and conserving Braille cells, Zhong and his group endeavored to omit tone annotation based on tone number or syllables. But these methods did not align with the reading habits of visually impaired individuals, as revealed in their pilot study.

Recognizing the potential to omit annotations by considering the frequency of tone occurrences in the initial consonants of Chinese syllables, Zhong conducted a quantitative analysis of 10 million Mandarin Braille cells. This rigorous examination led Zhong to discover an effective method for incorporating tones into Braille in 2016.

China introduced its Chinese Common Braille Scheme in 2018 following a two-year trial period, marking an end to the 70 years of non-tonal Braille.

To gradually implement the common Braille scheme, textbooks used in schools for the visually impaired were progressively updated with the new scheme starting from the first grade. The common Braille system now encompasses all foundational education from the first to seventh grade in China.