>>9180617Because Coco whole deal for a while was "Hahaha, I'm from USDA!". And she was there, from another world, to learn JP. Her being bad and speaking relatively imperfect JP was funny and a neato character quirk in her era.
Kiara's whole bio is: "An idol whose dream is to become a fast food shop owner. Kiara is a phoenix, NOT a chicken or turkey. (Very important)". Literally her speaking JP makes no sense and is super fucking annoying.
Actual reasoning outside of the characters:
Coco speaking with some EN and JP was because she actually really fucking sucked at JP when she first started. Like, seriously bad. There's clips of her and Kanata making fun of it years later. Her repeating herself was done for A) to help EN watchers to watch and B) because she probably needed to say things in English sometimes to work out how to say it in JP. Or to ensure that what she meant to say was clear. For example, she might say something in JP kinda weird, then follow up with EN to make sure people knew she meant to say that in JP. It felt more like a habit and personal tick that stuck.
Kiara is almost fluent in JP and English. Her repeating herself is a waste for her position in the company. IF JP bros want to watch an EN chuuba, they probably expect them to speak in EN. Of course, injecting some lines in JP is good if you notice a large JP following, but as mentioned WAY earlier in the thread, JP reps should be used creatively instead of just repeating yourself. For example, as others have pointed out, Pika uses her EN skills to sometimes play EN games. If any EN Girl used her JP skills to play JP games, that would sell like hotcakes. Instead they don't and it comes off as grating. Because people, whether thinking of that or not, understand that wasting your time repeating yourself is annoying.