Specialized markup languages are necessary because computers normally deal with linear text and more limited character sets (although increasing support for Unicode is obsoleting very simple uses).
[3] Computer algebra systems such as Macsyma, Mathematica (Wolfram Language), Maple, and MATLAB each have their own syntax.
When the purpose is informal communication with other humans, syntax is often ad hoc, sometimes called "ASCII math notation".
These allow entering formulae using a graphical user interface, and converting to standard markup languages such as MathML.
The lack of compatibility led some prestigious scientific journals to refuse to accept manuscripts which had been produced using Microsoft Office 2007.