Regarding Octave/Matlab, as I said before I've been using m-scripts for 6 years now and my Bachelor's thesis was written solely in this tool. This principally consisted on writing preprocessing functions for treating medical signals and then implementing the Particle Swarm Optimization algorithm to optimise the training set used for a machine learning model. I have also used it to execute simple filters over images. Nowadays I keep using it as a prototyping environment. Finally, I once took a 4-hours-course at college to learn about OpenGL but I don't have further experience with it nor Qt.
* 'Please describe your experience with other programming languages.''
I have experience working with Python 2.7.6. For my Master's thesis I created an open tool for open research data reutilisation and the scripting was whole written in Python. These scripts mainly used libraries like matplotlib, numpy and pandas. In addition to that, Tensorflow was utilised through its Python API so I could implement a simple logistic regression model. As a side project, just for the sake of learning, I once used Python and Keras (over Tensorflow) for building a cat/dog images classifier training a Convolutional Neural Network.