ちゃんとよぶ呼ぶto call someone "chan"こども子供ちゃんchild (informal and affectionate)ともだち友達ちゃんfriend (informal and affectionate)ねこ猫ちゃんlittle cat (informal and affectionate)あかちゃん赤ちゃんbabyいもうと妹ちゃんyounger sister (informal and affectionate)おははちゃんお母ちゃんmother (informal and affectionate)かのじょ彼女ちゃんgirlfriend (informal and affectionate)せんせい先生ちゃんteacher (informal and affectionate)ふぁんファンちゃんfan (informal and affectionate)
As you can also tell from these beautiful, far from Japanese, looks, Yuna is not pure-blood Japanese. She's a quarter-blood with a westerner as grandmother.