title_body: Phonetic IPA sounds problem to transfer to ePub format
upvoted_answer: You might want to try to embed a different font. Free fonts with good IPA coverage are:
  
  Charis SIL
  
  Source Sans Pro
  
  If embedding a different font didn't solve your problem, it was most likely caused by the epub converter that you used.
  What's the source file format and what tool did you use to convert it to an epub file?