Why do new members of After School have English names?

Many girls have been entering After School in the past year. First UEE joined just in time to debut with Diva, then Nana and Raina joined to replace Soyoung and now Lizzy has joined as the newest student member. The original members all use their real Korean names,�Kahi (??), Jungah (??), Jooyeon (??),�Becca and�UEE (??; close enough!). However, Nana (real name: Jin Ah / ??), Raina (real name:�Hye Rin / ??) and Lizzy (real name: Sooyoung / ??) have gotten new English aliases �for themselves. Why is that? Pledis Entertainment rep said,

"We want to get them known to the public faster with easy English names. The English names are matched with their characters. We wanted the new members to find their place in the group fast. Another reason is that their real names interfere with other celebrities' names."