The MathWorks, Inc. [L1 ] styles MATLAB [L2 ] as "the language of technical computing".
"GNU Octave is a high-level language, primarily intended for numerical computations", according to its home page [L3 ]. Its language "is mostly compatible with Matlab."
http://merlin.inescn.pt/~qual/tk_octave/index.htm ?
Tkoctave
[Link to article on Open Source vs. proprietary for scientists.]