"Little sister" is 'imouto,' while "littlest sister" is 'ichiban shita no imouto.' (Japanese: 一番下の妹)
Little sister
私は妹が二人います。 (watashi WA imouto ga futari imasu.)
Ane, older sister. Imouto, younger sister.
giri no oneesan=older sister in law giri no omooto=younger sister in law
You may say 'imouto.'
The term 'little sister' could be translated as 'imouto', to say 'my little sister' you could say 'watashi no imouto'. But remember, if you are going to refer to someone else's little sister, you must say 'imouto-san', 'san' being the honorific, which are a key element of the Japanese language and etiquette.
The cast of Imouto - 2005 includes: Reiko Mikami as Imouto
You may say 'imouto.'
'Imouto.'
Little sister
Imouto - 2005 was released on: Japan: January 2005 (limited) Taiwan: January 2005 (limited) USA: April 2005 (limited)
'(This/That/She) is my younger sister.'
The cast of Nemidare hitozuma no imouto - 2010 includes: Minami Aoyama as Asada Sakiko Mari Yamaguchi as Midori Sayama
"Little sister" is 'imouto,' while "littlest sister" is 'ichiban shita no imouto.' (Japanese: 一番下の妹)
Little sister
If you are looking for your younger sister you would say "watashi no imouto wa doko deshouka?" [私の妹はどこでしょうか]If you are looking for your older sister you would say "watashi no one wa doko deshouka?" [私の姉はどこでしょうか]So one is older sister and imouto is younger sister.