Apart from his specific accent choice, which is a bit odd, Robert Downey Jr. and the rest of the cast have few memorable lines. Besides Dolittle nabbing Robert Downey Jr. in the titular role, the family-friendly movie has enlisted an incredible voice cast of huge stars including fellow MCU actor Tom Holland, Rami Malek, Emma Thompson, Kumail Nanjiani, Octavia Spencer, John Cena, Ralph Fiennes and Selena Gomez providing their voices, and Antonio Banderas and Michael Sheen as live-action characters.
Article source: https://www.cinemablend.com/news/2482351/will-robert-downey-jrs-popularity-be-enough-for-doolittle-despite-bad-buzz