This was suggested by Mai_likes_Anime so here it is! and sorry if I spell acnologia wrong...

Igneel: Acnologia.

Acnologia: Igneel.

Igneel: The dragon slayers will defeat you

Acnologia: I am far stronger then them.

Igneel: They have grown much in strength, don't be so sure...

Acnologia: I do not fear a measly human!

Igneel: Then your confidence may be your demise

Acnologia: You are merely trying to scare me, but I'll tell you now, it won't work.

Igneel: Like I said, you won't stand a chance...

Acnologia: I wait for the day that I may destroy them!

Is that good? I dunno...