I checked About.com's Urban Legends to make sure this true. This is what they said:
"Comments: Theodore Roosevelt indeed wrote these words, but not in 1907 while he was still President of the United States. The passages were culled from a letter he wrote to the president of the American Defense Society on January 3, 1919, three days before Roosevelt died.
""Americanization" was a favorite theme of Roosevelt's during his later years, when he railed repeatedly against "hyphenated Americans" and the prospect of a nation "brought to ruins" by a "tangle of squabbling nationalities."
"He advocated the compulsory learning of English by every naturalized citizen. "Every immigrant who comes here should be required within five years to learn English or to leave the country," he said in a statement to the Kansas City Star in 1918. "English should be the only language taught or used in the public schools."
"He also insisted, on more than one occasion, that America has no room for what he called "fifty-fifty allegiance." In a speech made in 1917 he said, "It is our boast that we admit the immigrant to full fellowship and equality with the native-born. In return we demand that he shall share our undivided allegiance to the one flag which floats over all of us."
I had to pass this on my friends -- everyone knows how I feel about illegal immigration, or immigrants who come to America under false pretenses. I echo every sentiment Teddy Roosevelt just stated. If you want to come to America, come. But if you don't want to be an American and fully embrace all that America stands for . . . go home. We don't need you here.
This is a land of promise and hope, but only for those willing to learn English, fly the American flag and fight for this great nation. It's as simple as that.