Girls' Generation's Sooyoung had a funny take on Seohyun trying to use informal speech.
On September 4, a video titled "A Real Conversation Between Close Friends That Needs Clarifying Every 3 Minutes" was uploaded to Hyoyeon’s YouTube channel, "Hyoyeon’s Level Up." Sooyoung appeared on the show, showcasing her humor alongside host Hyoyeon.
During the episode, Sooyoung talked about how Seohyun once tried using informal speech at Tiffany's birthday party, which also marked Girls' Generation's 17th anniversary. She shared, "At the party, we were blowing out the candles and saying, 'Congratulations!' Then I said to Seohyun, 'Hey, it's been 17 years—why not speak informally now?'"
Sooyoung expected Seohyun to hesitate, but to her surprise, Seohyun said, "Should I try? I could do it." Sooyoung humorously reenacted Seohyun’s reaction, saying, "I was like, 'Has she been waiting for this moment? Does she really want to speak informally?'"
Despite Seohyun's attempt, Hyoyeon revealed that she couldn't go through with it in the end.
Sooyoung sympathized with Seohyun, saying, "I get it. After using formal speech for 17 years, it would be weird to suddenly change." Hyoyeon agreed, adding, "We’re close enough, but it's just hard to switch after so long."
Hyoyeon then asked, "Would it even be good if Seohyun spoke informally to us? What’s the benefit?" Sooyoung made a playful face, and Hyoyeon suggested, "Maybe she could mix both formal and informal speech?"
Sooyoung agreed, saying, "Yeah, that would work better. Otherwise, it’d feel awkward." Hyoyeon added, "It’d be strange for me too. Maybe she can ease into it, like YoonA does, and that would help her feel more comfortable with us."
Source [1]