From Nookipedia, the Animal Crossing wiki
Mabel (きぬよ, Kinuyo) is a character in the Animal Crossing series, co-owning the Able Sisters tailor shop, one of the two stores that can be found in the player's town, with her older sister, Sable. She is the charismatic one out of the sisters, who assists customers with their purchases.
 Physical Appearance
Mabel is a blue hedgehog with brown-orange cheeks and black eyes, eyebrows, and snout. Like her sister, she has no visible mouth, so instead visibly talks by moving her nose. She wears a green and white gingham apron and has a head full of large, spiky bristles.
She does not directly speak about her past - which is given away by Sable once talking to her. She may bicker from time to time with Sable, about who does most of the work within the business. She rarely mentions her parents, but from what is learned through Sable, she was too young to know who they were at the time of the crash. She was raised by her sister, as at the time she was an infant.
Mabel works at the shop, The Able Sisters, along with her older sister Sable as a store clerk. She helps the player design clothing patterns and sells the player clothes and umbrellas.
Her role is the same as it was in Animal Crossing, except now she also sells hats and accessories.
 January Blues
In January, Sable will get depressed, much to Mabel's bewilderment. Eventually, after talking to Sable enough during the month, she reveals a huge secret: she and Tom Nook were best friends before he moved to the city. Naturally due to Mabel's age, she knows little of the subject, but does have experiences to do with the subjects. The following can be matched with Sable's statement to get an accurate picture:
Her role in Animal Crossing: City Folk is virtually unchanged, but she now assists the player with making PRO designs. When talking to her, she soon learns that she may in fact have an older sister called Labelle, a worker in GracieGrace - a store in the city. Mabel has no contact with Labelle, due to her having an argument with Sable, who felt she abandoned the family when their parents died. Mabel wishes to get them talking again.
 Other Appearances
Mabel appears as a trophy and will occasionally appear in the background of the Smashville stage.
 Names in other languages