I have nearly no experience in coding. To build a half-decent website, what programming language should I learn (take a course) and study to be able to fairly successfully create my own website?
For example, what programming language for blogging?
What language for interactive (client-side) actions?
What language for videos (similar to Youtube)?

I'd love for some answers to some of the questions! Thank you, in advance!

look at http://forums.d2jsp.org/forum.php?f=120 and the relevant subforums, post there to get your answers

html5, javascript, php

Hey mate

there are alot of good tutorials out there
You can make a simple site using just the following:
HTML/XHTML
CSS
PHP

After that it depends on what kind of site you are making
but there is:

AJAX
JavaScript
MySQL

you can go to codecademy.com and try the html/css/javscript(jquery)/php courses
really good website to start coding