Bharati Braille:
Detailed Information
Bharati Braille
is based on the principle that the six dot system could also be used as
a script for Indian languages. Essentially, the assignment of cells to
the aksharas is based on phonetic principles and in many cases, the cells
assigned for the English letters are used for similar sounding aksharas
in Indian languages. Bharati Braille is common to all the languages with
very few variations to cater to the differences in the aksharas across
the languages.
Bharati Braille is
the standard prescribed in India for preparing Braille documents in all
the Indian languages. The standard uses the six dot system as in normal
Braille but the cell assignments correspond to the aksharas of the Indian
languages. Very simply, Braille is used as another script to write text
in all the Indian languages. This is possible on account of the phonetic
nature of the languages where the writing systems follow rules for displaying
syllables rather than the basic vowels and consonants.
The six dot system
provides for displaying 64 different patterns. Of these, only 63 may be
used for representing the aksharas. The 64th pattern is a cell without
any dots and is implied to represent the space character. In English Braille,
the 63 different cells represent the letters of the alphabet (26), ten
punctuation marks, fourteen frequently used short letters and the rest
assigned special meanings.
It may be noted that
the assignment of meanings to each cell has no direct relationship to the
set of displayable ASCII characters (96 in use). Braille is perhaps the
earliest of schemes where a displayed pattern represented much more than
the information conveyed by the individual cell. In other words, Braille
is a scheme where some kind of data compression is applied. The meaning
of a cell is to be interpreted in the context in which the cell is present,
such as the cell preceding it, whether it appears in the beginning of a
word, etc.. The tutorial on
standard Braille presented in separate pages has relevant information.
A sheet of printed
Braille will have a series of cells embossed on thick paper and the embossing
can be sensed by passing one's forefinger over each line of embossed cells.
The size of a Braille cell has been standardized but small variations exist
in the standards followed in different countries. The horizontal spacing
between the two dots in a row is about a tenth of an inch or approximately
2.4 mm. The spacing between vertical dots in a cell is also about the same
2.4 mm. Cells are spaced between 6.4 and 7.2 mm horizontally and between
10.2 and 13.0 mm vertically. A standard sheet of Braille has about forty
cells per line and may contain 20 or more lines.
Bharati Braille is
thus a system for writing syllables using a basic set of 63 shapes, each
corresponding to a cell. Here, the most basic approach to writing syllables
using generic consonants has been used. A syllable in Indian languages
can take any one of the following forms.
A pure vowel V
A basic consonant and a
vowel CV
A conjunct with two or more
consonants and a vowel CC..V
Besides the
syllables, special symbols are also used. These include modern punctuation
marks as well.
In Bharati Braille,
the basic vowels and consonants of the languages have been assigned individual
cells. Across the languages of the country, between 13 and 18 vowels are
in use and the consonants are between 33 and 37 in number. Thus more than
50 cells have been assigned for the basic vowels and consonants leaving
the rest for special marks.
The cell assignment
for a consonant assumes that the consonant has an implied vowel "a" as
part of it. A pure consonant ( also known as a generic consonant) has no
vowel and so to distinguish a basic consonant from its generic equivalent
a special symbol is used in the writing systems. this is known as the halanth
and its shape is a language specific ligature added to the shape of the
basic consonant. Bharati Braille has set apart one cell for this purpose
and this cell placed before the cell for a basic consonant turns it into
a generic consonant.
The idea here is that
one can use this principle to write syllables in the CC...V form simply
by concatenating the cells for each generic consonant.
The cell assignments
corresponding to the basic vowels and consonants are similar to the assignments
of the English alphabet where the sounds match. But only about 25 can be
matched this way. Cells in standard Braille which correspond to specific
two letter contractions have been chosen to take care of the aksharas such
as the diphthongs and the aspirated consonants. In assigning the cells,
a superset of the aksharas from all the Indian languages (including Urdu)
has been taken into consideration.
Bharati Braille was
conceived of as early as 1951. It is known that there were different schools
of thought on the cell assignments. The standard was evolved after many
discussions and the scheme which followed the assignments for Standard
English Braille was ultimately accepted.
Here are the assignments.
In the illustrations, a rectangular frame has been superimposed on each
cell to identify it easily. The frame is not part of the cell and will
not be present in actual Braille documents.
It may be seen that
in a few cases, the same cell has been assigned for different aksharas
across different languages. This is a consequence of the fact that the
basic set of vowels and consonants actually vary across the languages.
Since only 63 different cells are possible (the 64th will not have any
embossed dots and thus refers to a space character), multiple assignments
are unavoidable.
It is also observed
that some of the aksharas have been assigned two cells. The first of the
two cells will invariably be a cell with just one dot, typically dot 5.
The understanding here is that a cell with dot 5 alone is a special cell
implying that the following cell has to be interpreted differently. Such
schemes where a special symbol is employed to provide specific interpretation
of the following character, are common with computer systems and the special
character is known as the Escape character. It is remarkable, that Braille
had employed this scheme long before computers came into the picture.
Basic
rules for preparing Braille text
Bharati Braille conforms
to the syllabic writing system followed for all the Indian languages and
syllables are just written using the cells assigned for the consonants
and vowels.
A pure vowel is always shown
using the cell assigned.
A basic consonant is always
shown using the cell assigned for the consonant.
A consonant vowel combination
is shown using the respective cells. Normally a pure vowel will not
follow a consonant and will appear only at the beginning of a word. However,
there are many exceptions to this rule as will be explained below.
A syllable is shown using
the cells assigned to each consonant and preceded by the halanth
cell for all but the final consonant which may have a combining vowel.
Punctuation
and other symbols
The idea in Braille
is that a visually handicapped person should be able to read text just
as a normal person. So Braille includes all the punctuation marks and other
symbols normally seen in printed text. However, since all the text has
to be shown only using the 63 cells, certain conventions exist where the
interpretation of a given cell may depend on the context. Such specific
interpretations are normally effected through specific escape characters.
These are the most
basic punctuation marks but there are others such as square brackets, number
sign etc. One observes that the punctuation marks are distinguished by
the absence of the dots in the first row. Notice that both the Parentheses
have the same assignment. From the context the reader will be able to correctly
identify them.
It turns out that
in Bharati Braille, the punctuation follow the same assignments as in standard
English Braille.
Numerals
The limit on the number
of cells poses some problems when it comes to representing the numerals
and related symbols. In standard Braille, as well as in Bharati Braille,
numerals in normal text are represented in terms of the first ten letters
of the alphabet i.e., a b c ...... j.
To distinguish the
numeral from the letter of the alphabet, a special cell is placed before
the numeral. This cell is known as the Number sign. In standard Braille,
the rule followed in using this special number sign is that it is placed
in front of a string of numerals where the string has a specific interpretation.
The number sign is not placed before every numeral. It is present
at the beginning of any group of numerals that have specific interpretation.
Special
cases requiring specific attention
Syllabic writing systems
have their complications as well. Besides, it may be necessary to effect
compromises on the assignment of cells, if a number of additional symbols
have to be mapped, in a language specific manner. So it is inevitable that
when Bharati Braille is read, one must keep in mind the language. There
is room for confusion if multilingual text in Indian languages is printed
in Braille unless the person is completely familiar with the meaning of
each cell. Unfortunately, the designers of Bharati Braille did not think
of an effective approach to indicating a language switch. The responsibility
rests with the reader.
Here are some rules to keep
in mind.
Mathematical
point and comma
The mathematical period
(point) and the comma written to separate groups of numerals have been
assigned cells different from those for the normal full stop (period) and
the comma. This permits one to correctly identify the context in which
the numeral string is present and interpret the same properly.
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