The Jazz Singer was a singing goblin who, accompanied by goblin musicians, performed jazz songs at the Blind Pig. She created smoky images from her wand to illustrates her lyrics (WFT).
Singing, and producing smoky images from her wand (WFT).
Other canon notes and references
The song of the Jazz Singer:
The phoenix cried fat tears of pearl,
When the dragon snapped up his best girl,
And the Billywig forgot to twirl,
When his sweetheart left him cold,
And the unicorn done lost his horn,
And the Hippogriff feels all forlorn,
’Cause their lady loves have upped and gawn,
Or that’s what I’ve been told— (WFT).
"Jazz Singer" here is just a label used in the script for an otherwise unnamed character.
"The Jazz Singer" starring Al Jolson was one of the earliest movies with sound, made in 1927 - one year after the events in Fantastic Beasts and Where to Find Them. The plot was about a young Jewish man in New York City who sang in a beer hall and was punished by his devout father, who was a singer ("Cantor") at their synagogue. The father uses the term "jazz singer" as an insult because it was thought of as a lowly profession. The boy ran away from home to seek a career in music, changing his name from "Jakie Rabinowitz" to "Jack Robin." But he later returned to his Jewish roots when his father fell sick and couldn't sing on the holy day of Yom Kippur. (Source: Wikipedia).
Note that, unlike British goblins, this singer is allowed to use a wand. That American goblins have this right while British goblins do not adds complication to the racialized undertones that accompany goblins in general and this jazz-singing one in particular. -BB