No one is immune from bad code. As far as teaching technique, that's debatable. I think JS is a great starting place as its build/runtime is already (I would hope) familiar to the learner. Then from there, go up, down, and in the middle. C for low-level. Python might be a decent choice.
You don't have to spend a couple of years in each. In fact, since the field is so big, it really is impossible to catch up to 20 years of experience with 7 languages in 2 years. Focus on something you LOVE and go into that domain. If it's web, do PHP/JS (or whatever stack), for iOS/OSX do Objective C. For performant native apps, probably C, Python, or C++. Kernel, C. Etc. Or perhaps, a functional language like Erlang might be more suitable to your field.
It is possible to get 20 years of experience in about 5-7 nowadays with the tools available if one focuses and spends time developing one's career and isn't afraid to read code with or without help from IDEs (because most code is shitty). This post is total bullshit.