The phrase "formative phase" is correct and usable in written English.
It can be used to describe a period of development or growth, often in educational or developmental contexts.
Example: "During the formative phase of childhood, children develop essential social and cognitive skills."
Alternatives: "developmental stage" or "initial period".
This fine film, narrated by Jarvis Cocker, explores the most thrillingly formative phase of his career.
That takes time, he concedes, and the Garde is in a formative phase, learning from process and exploring possibility.
This period marked the end of the formative phase of Mesopotamian civilization.
Like Surrealism, the New York School had its formative phase, its classic period and its decline into repetition and imitation.
Exhibited last year at Luhring Augustine on a wall-size screen, "Touch" documented in sun-washed color a formative phase of the present theme.
In 1970 he was recruited during the formative phase of the Department of Medicine at Penn State Hershey where he maintained a solo practice in Internal Medicine and Gastroenterology for 18 years.
He and Mr. Lambert ultimately did make a short film about the band's formative phase, and some of the footage is included in "The Kids Are Alright," the 1979 documentary about the Who.
The Brooklyn-born Paul Thek (1933-98) remanns an elusive presence in contemporary art, and this show, organized by the stage designer Peter Harvey and the art historian Jonathan David Katz, fleshes out, for the first time, an early, formative phase in Thek's career, when he drew his primary influences from a network of contemporary gay men in the arts, among them Peter Hujar.
But it has taken the work of a much smaller institution, the Leslie Lohman Museum of Gay and Lesbian Art, to fill out, for the first time, a very early, formative phase in Mr. Thek's life, when he drew his primary influences from a network of young gay men in the arts.
