calc-language is a variable defined in `calc.el'.
Its value is

Language or format for entry and display of stack values. Must be one of:
nil Use standard Calc notation.
flat Use standard Calc notation, one-line format.
big Display formulas in 2-d notation (enter w/std notation).
unform Use unformatted display: add(a, mul(b,c)).
c Use C language notation.
pascal Use Pascal language notation.
fortran Use Fortran language notation.
tex Use TeX notation.
latex Use LaTeX notation.
eqn Use eqn notation.
yacas Use Yacas notation.
maxima Use Maxima notation.
giac Use Giac notation.
math Use Mathematica(tm) notation.
maple Use Maple notation.