On August 31, IZ*ONE's official Twitter account shared a picture of members' handwritten letter to Won Young for her birthday. Among the well-wishes from members, fans have noticed Nako, Hitomi and Sakura's dramatically improved Korean. Fans compared members' letters to Eun Bi, written 11 months ago, with those addressed to Won Young.   

Below on the top is Nako's letter to Eun Bi and on the bottom is that for Won Young. Nako wrote, "Eun Bi unnie!!! Happy birthday. I want to talk to you every day from now on. Hope you have a great year."  For Won Young, she says, "Are you still 16 years old? It's weird kk. It feels like we talked a lot recently because we share the room. On the stage you are professional, but when we eat tacos together and share scary stories, you are super cute because it really feels as if you are my little sister. I hope you have a great year. Happy birthday."

Below are letters from Hitomi to Eun Bi and Won Young, respectively. Hitomi goes "Happy birthday~ I like your voice and dance moves. I continue to admire you!" In the letter for Won Young she wrote, "Our maknae Won Young! Happy birthday~ Super cute, pretty, stylish, smart and charming Won Young is my ideal type~! Continue to sleep well and eat well!"

Below are Sakura's letters to Eun Bi and Won Young, respectively. For Eun Bi, she wrote "Eun Bi unnie! Happy birthday~ I like everything about you!". For Won Young, she says "Won Young, happy birthday~ our cute, cute maknae. Your style, visual and talents are those of genius'! We can shine because you are shining at the center of our group. Tell us if anything happens. Eleven unnies will run to you!"

Were you surprised too, at how much they have improved within less than a year?