The skills learnt should be transferrable to Octave which is Matlab compatible.
[Speaking of cvxopt, originally written in matlab] "Fortunately, it has since been rewritten in a real programming language." - Stephen Boyd
I don't know of what other resources are available, but I do know I've seen some that use Matlab. I've never played with Octave much, so I don't know how compatible it is; can you just directly copy Matlab code, or do you need to do translations?
Anyhow, if there's a book that uses Matlab rather than BASIC, and could be used in Octave, that might be more readable. I would find C, C++, Python, or Rust more familiar, though.
I'm not an expert, but I believe Octave is pretty compatible, at least with the core language. I think there are some "extra" features and libraries that don't exist in Octave, but it should be fine for many scenarios. FWIW, the earlier version of Andrew Ng's machine learning class on Coursera was Matlab / Octave based, and students using Octave were able to do everything required there with no problems.
You can find some more detailed comparison here:
https://en.wikibooks.org/wiki/MATLAB_Programming/Differences...