Here are some quotes by and about Helen, including some from those who knew and loved her.
"I just put it in at one of the rehearsals, a sort of interlude. It's hard to explain - I haven't explained it to myself yet. It's like vo-de-o-do, Crosby with boo-boo-boo, and Durante with cha-cha-cha." -Helen Kane, on the creation of her "boop-boop-a-doop"
"I thought you might like to know that her first introduction to “show business” was when her older sister, Gertrude took her to a talent show. [Gertrude] had entered the contest and while she was on the side waiting, Aunt Helen was also asked to perform - because she was so cute and the management wanted her on stage. It was at this time, she said, she was inspired and added the famous 'boop boop a doop' into her song. According to her, the audience went wild and she won the contest - beating out her own sister." -Melody, Gertrude's daughter and Helen's niece
"In our neighborhood in the Bronx, Aunt Helen would sit on the stoop and sing for everyone. Neither her nor Uncle Dan drove, so we would pick them up in Jackson Heights and sing all the way." -Mickey, Helen's niece
"I had a song sheet of Helen Kane and the spit curls came from her. So I just designed a little dog and put cute feminine legs on her and the earrings which developed later started out as long ears. I suppose I used a French poodle for the basic idea of the character." -Grim Natwick, creator of Betty Boop and Snow White, on his inspiration for creating Betty Boop
"...[Mae Questal] was only 17 when she won a contest to find a look-alike for Helen Kane, a singer then known as the boop-oop-a-doop queen. Questel imitated the singer in vaudeville shows...Her stage work won her a contract to take over the cartoon voice of Betty Boop, which she did in more than 150 animated shorts before the character was retired in 1939." -Obituary for Mae Questal, voice of Betty Boop; Los Angeles Times, January 9, 1998