title_body: Simplified Version of IPA?
upvoted_answer: If you're notating a language that uses [β] or [ɓ] but does not distinguish it from [b], that is, if there are no words such that changing one of these consonants to the other changes the meaning of the word (perhaps because [β] occurs only between vowels and [b] elsewhere), then for most purposes you write them all as /b/; so that is a “simplified IPA”.  This is called broad transcription, written with slashes to distinguish it from narrow transcription using brackets.  A famous example: English /p/ includes both [p] and [pʰ], which are distinguished in many languages including Zulu, Hindustani, Mandarin.
  No language makes phonemic distinctions between all pairs of phones represented by distinct symbols in IPA; but every symbol exists because some language contrasts it with others.