The LanguageHandler is an old class used by SketchUp’s extensions since the early beginning. The names had that quirky naming of capital letter because they where written by C++ programmers.
The examples stem from this time - before the LanguageHandler was made part of the API.
(That being said, I personally don’t like the LanguageHandler being made into the API as-is - it could have done with some improvements. Though that was before my time.)