Sunday World (an Irish magazine) has a small article about Saoirse Ronan. In it are a couple of Host relevant quotes.
On turning 18 on The Host set:
“Best on-set birthday ever,” she giggles. “I went to my trailer and it was decorated with balloons and streamers. I had cake!”
On the double role of Wanda/Melanie:
“I think playing two characters in the same film is inviting to any actor,” she explains. “For most of the film we hear Melanie’s voice because it’s the voice Wanderer hears in her head. Melanie has kind of a Southern accent.”
On her Melanie voice:
“Saoirse and her voice coach based her accent on Jane Fonda. ‘In the 1970s she had a beautiful way of speaking that you don’t hear so much these days, almost foreign sounding.'”
(side note: did anyone hear the southern accent in the trailer? Maybe there wasn’t enough to hear it.)
Source: Sunday World