Allyson sings in English, French, Portuguese, Italian, and Spanish. The songs she performs are drawn from a variety of genres, including bossa nova, blues, bebop, samba, jazz standards, and other jazz modalities, and also ballads, pop standards, the Great American Songbook, soft rock, and folk rock. She has also recorded vocal performances of several instrumental jazz compositions, using both scat and vocalese techniques. She has recorded 12 original studio albums for the Concord Jazz label, and in 2009 she released a career-spanning "best of" collection. Her first all-original record, Some of that Sunshine, was released in August 2018 to rave reviews, with Jazz Times writing that "Allyson unleashes her equally impressive dexterity as a songwriter."