User blog comment:IamJakuhoRaikoben/Chapter 394: Juvia vs. Keith, Review./@comment-71.50.113.114-20140725153119/@comment-24936031-20140725171654

Well, NoNick, I think Lucy may be developing 'the next level of celestial spirit magic', like building bonds to the point that instead of needing to summon the spirits themselves, their magic becomes hers (not full on transfer, more like a copy+paste effect). Not that she would be belting out Urano Metria constantly, but allowing steady growth.