"commend you on" is correct and can be used in written English.
You can use it when you want to express praise for someone's accomplishment or effort. For example, "I commend you on your hard work and dedication to this project."
"Dear Sir," read one, "I'd like to commend you on the new size of your paper.
I commend you on your Sept. 26 editorial "The Healthy Politics of Iraq".
Christopher Bonnett, Houston.: I commend you on your own moral revulsion for the denizens of corruption of both parties currently ensconced in the House of Representatives.
I commend you on your choice of Milan Hlavsa as an important figure who died in 2001 ("Prague Rock," by Paul Berman).
I commend you on the deceit; it's a perfect facsimile of an actual OBO - the spot-on impersonation of the usual emailers, the lame riffs, the self-loathing.
While I disagree with virtually every editorial position that The New York Times takes and the way it covers many of its stories, I must grudgingly commend you on your handling of the Jayson Blair affair (front page, May 11).
A colleague commending you on your performance?
As chairman of NYC & Company-the ConventIon and Visitors Bureau, I commend you for focusing on the need to expand the Jacob K. Javits Convention Center and the addition of a stadium as part of an overall West Side development plan.
But her campaign tactics are increasingly reminiscent of Lee Atwater and Karl Rove, and I commend you for calling her on it.
I want to commend you for taking this on.
I commend you to my friend, Mark Twain on the power of humor: "Against the assault of laughter, nothing can stand".
