It’s nice to have a software, it’s better to control it.
There are many proprietary software to analyze measurements. The worst I have ever seen was a wrong physical model implemented in a program. This error rendered all my results wrong and the proprietary license made me dependent on the willingness of the software publisher.
To avoid this situation, all software we develop together will be libre. As a user, this means you will have access to the source code. Depending on your goals, you may choose to open it to a wider community which can access and improve it.
You can pick either Python or Matlab, two popular languages among scientists and engineers. Part of the code may be written in JavaScript.