What does "I Know" mean?

Recently, I submitted an application as part of the work I'm doing for my next job.  As a programmer, I needed to communicate what languages I knew.

I'd like to avoid giving the impression I'm better than I am.  That might get me the job but I won't keep it.  If they're willing to take on an energetic learner, then I want them to know what they're getting so there's no issues or communication that could result in firing or bad feelings.

How can a job-hunting programmer clearly communicate their skill in a language?  I've already asked a related question on Programmers.SE.  There were a lot of excellent answers but let's focus on our topic: a resume.

One solution is to simply group them all together, perhaps ordered by experience.  The problem here is that there is still a lot of ambiguity.  If I've listed "C++, C#, Python," does that mean I have 6 months or 6 years of experience in C++?

Another easy answer is to simply list the years you've worked with a language alongside the language.  This also leads to definition problems, as I've "worked" with Python for three years now but my skill in Python is nowhere near someone who's been using it professionally for three years.  This tactic may impress HR but I hope that any competent programming manager understands that experience doesn't make you a better programmer (for more on this, check out Peopleware).  Feel free to try this tactic if you want to impress a non-programmer.  I wouldn't use this.  If a non-programmer is the one hiring programmers, do you really want to work there?

So the simple approaches didn't work.  One could include all of the major projects one has completed.  This takes up a lot of time and space and you could run into NDA issues.

So what did I do?

I've divided up my programming experience into three categories:
Professional: Languages I've been paid to write in (for a significant period of time.)
Project: Languages that I have completed a decent-sized project in.  Something bigger than Hello World.
Familiar with: Anything that I've written in that doesn't fall into the above categories.  Something more than Hello World but less than a full project.  I also put languages here that I have built something in a while ago.  For instance, I once built a virtual stock market in C++ two years ago.  Naturally, my knowledge has lapsed somewhat.

I chose this system because it was easy for me to categorize my knowledge as well as explain the system to others.  In addition, I included a link to my GitHub account to (attempt to) provide proof that I could code.