ARPA language model documentation

Where can I find documentation on ARPA language model format?

I am developing simple speech recognition app with pocket-sphinx STT engine. ARPA is recommended there for performance reasons. I want to understand how much can I do to adjust my language model for my custom needs.

All I found is some very brief ARPA format descriptions:

• http://kered.org/blog/2008-08-12/arpa-language-model-file-format/
• http://www.speech.sri.com/projects/srilm/manpages/ngram-format.5.html
• http://www.speech.cs.cmu.edu/SLM/toolkit_documentation.html

I am beginner to STT and I have trouble to wrap head around this (n-grams, etc...). I am looking for more detailed docs. Something like documentation on JSGF grammar here:

http://www.w3.org/TR/jsgf/

There is actually not much more to say about the format than is said in those docs..

Besides, you'll probably want to prepare a text file with sample sentences and generate the language file based on it. There is an online version which can do it for you: lmtool