TRANSCRIPTION STANDARDS
Major governing bodies for phonetic alphabets:

• International Phonetic Alphabet (IPA): over 100 years of history
  
  
• ARPAbet: developed in the late 1970's to support ARPA research
  
  
• TIMIT: TI/MIT variant of ARPAbet used for the TIMIT corpus
  
  
• Worldbet: developed by Hieronymous (AT&T) to deal with multiple languages within a single ASCII system
  
  
• Unicode: character encoding system that includes IPA phonetic symbols.

Here is a chart classifying sounds using the IPA:


For a more detailed discusion of phone mappings across languages, see language independent acoustic modeling.