Do I really need to know more than one language if i want to make webapps?
I'd stick with one server side language for now - and Python (or any of the other languages you listed) is a perfectly good choice for that.
Basic notions of what Javascript would be important I think, and how and what Ajax type technology can do.
However, stretching the definition of "language" a little, I think you develop a reasonable understanding of html and css as these are integral to web-development.
I'm a liberal arts major and have a few ideas for some web apps. I've saved up enough money to hire someone to do the coding for me, but I want to pick up at least basic coding skills on my own. I'd rather not be the clueless founder.
I've started off with Python. So far, so good. Despite my liberal arts background, I've always been pretty mathematically inclined, even taking some advanced calculus classes in college.
My question is: if my goal is to make web apps and not actually land a job, is it really necessary to learn more than one programming language? I'm starting off with Python and I've found it flexible and powerful enough to meet most of my needs. Do I need to expand my oeuvre to PHP, Ruby, Java, etc.?