Question: If I were a "BizDev" guy and wanted to create a website that has similar functionalities as, say, Groupon or PayPal (I understand they're different), what languages would be best to learn?

I would suspect some front-end GUI paired with a back-end database system would be needed, but what languages specifically would be best?

As an entrepreneur with a degree in Mech. Eng. and Entrp., and I have done programming in MATLAB, some VBA, and some HTML. So I understand the logic behind programs, but don't necessarily know all the languages.

Any and all suggestions are most welcomed!