User blog comment:FairyRaven/Fairy Tail Chapter 328: Zodiac, Review and Commentary/@comment-112.205.41.120-20130421090106/@comment-7418318-20130421131309

There is definately a voice talking to Natsu right then. It might be his imagination or subconcious talking to him in Igneels voice, or Igneel himself, somehow making contact, but the voice is definately not part of the flashback.