"e?"
translation: what?

"wakannai"
translation: I dunno

"tabun"
translation: maybe, I think so

"gomen"
translation: sorry

"soonano?" or "sou?" or "hontoni?"
translation: really?

"omoshiroi?" or "tanoshii?"
translation: is it fun?

"chotto matte"
translation: wait a sec

"chigauyo"
translation: no way! (that's not true!)

(from eclip5e)
"majii de?!"
translation: really?!

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