"quietly changing" is an appropriate phrase that can be used in written English.
For example, you could write, "While the world around him was rapidly shifting, he was content to sit back and watch it quietly changing."
The first is that Canada is quietly changing.
Quietly changing tack, they stopped vilifying their most vociferous opponents as "counter-revolutionaries".
A few are quietly changing their mobile-phone numbers to avoid demands for cash.
It is quietly changing the curriculum at the staff college.Still pending is a constitutional reform to abolish unelected senators and the National Security Council, and allow the president to fire military commanders.
In his work with American Ballet Theater (where he is artist in residence) and New York City Ballet he is now quietly changing the course of ballet in the West.
The Node.js Community Is Quietly Changing the Face of Open Source Gregg Caines offers some thoughts on how Node.js development and use reflects a sea change in open source development in general.
Over the past few months, the company (part of Y Combinator's Summer 2012 class) has quietly been changing directions.
And they are, quietly but unquestionably, changing the rules about what it means to look like a president or prime minister.
"Our living wage campaign involving unions, students and voluntary organisations is sometimes quietly, sometimes noisily, changing lives," they wrote.
One aspect of the Egyptian uprising (among the others, most ongoing) that was overpowered by the wild acclamation of social media is something that has been quietly but powerfully changing societal norms over the last decade.
Singing quietly without dramatically changing key is good too.
