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Effective Practices for Description of Science Content within Digital Talking Books - Math Equations
For DTBs, the best solution is to render math in MathML and for the individual to use a reading system that provides a range of speech options. For all of the testing that can be done with blind and sighted experts and students, the solution to spoken mathematics comes down to offering a variety of styles that fit both the reading style of the individual and, in an educational setting, the pedagogy and learning style of the student. No single style or method of spoken math will cover every situation. Therefore, rendering the math in an unambiguous form, using MathML or (for some audiences) LaTeX, which can be then translated into speech in a variety of styles, should be the preferred practice.
Math rendered in MathML
MathML is a standardized mark-up language that allows authors to provide unambiguous representations of mathematical expressions. MathML can be written by hand using a simple text editor or a special equation editor such as Design Science's MathType, which translates mathematical notation into MathML. MathML does not provide a method for translating math to speech, however. Translating MathML into spoken English (or any other language) is the job of the MathML-reader or DTB-reader software.
In the best of worlds, users will be able to decide how they want math communicated to them. In a simple example, some readers may want to hear math spoken in plain English; for example, "two X open parenthesis three Y plus four Z close parenthesis." However, more experienced readers will desire shorthand in order to move through equations more quickly, reducing common expressions like "parenthesis" to "paren."
In an educational setting, another factor that must be considered is the pedagogical context in which the math is being presented. For example, a teacher may want a student to hear "X superscript two" as opposed to "X squared" in order to test comprehension of math notation.
In the end, the choice of how best to convert MathML to spoken English will be affected by the user's knowledge of the subject and his or her comfort with Nemeth code, LaTeX, or other math languages.
Nemeth Code
Nemeth code is an unambiguous language for translating math to Braille. Nemeth code has been in use for many years and is well appreciated by those who use it as the gold standard for representing math in Braille.
gh's MathSpeak renders MathML into spoken Nemeth code and provides many shortcuts for spoken mathematics. Indeed, MathSpeak enables the user to read math using several levels of verbosity, from having all words spoken in full to a rapid-fire shorthand. However, MathSpeak requires one to learn Nemeth code, in which even basic constructions, such as "begin-begin fraction," can baffle the uninitiated.
LaTeX
Math can also be rendered in LaTeX, an open-source typesetting program. Math in LaTeX is typically transmitted to a refreshable Braille display or translated into Braille via tanslation software such as
Duxbury. Some people do read raw LaTeX; however, this seems to be limited to mathematicians and other STEM professionals.
Spoken Math
When MathML is not used and equations must be read aloud, it is best for the reader to be a subject expert who can read the math in a clear, unambiguous manner. One widely used resource is "Larry's Speakeasy, Handbook for Spoken Mathematics." Similar to Nemeth code, Larry's Speakeasy provides a system for reading math in a non-ambiguous manner. While it is a good guide, it is not comprehensive. View other math resources.