No code other than E starts with 0000. No code other than i starts with 0001. And so on. As an extreme case, no code other than e starts with 01. You don't have things like E = 0000, space = 000, where you wouldn't know what to do if you find three zeroes.
Look at your encoded string: 0000101100000...
You read the first zero. You know the code is one of E, i, y, l, k, comma, or space. The next zero means it's not k, comma or space, but E, i, y or l. The next zero means it is E or i. The next zero means it's an E. When you know which code it is, you know you have parsed all the bits for that code.
Then you have 101100000... The 1 means you have e, r, s, n or a. The next bit is 0, so the code is e. Again, you're done with that character.