It would be up to each school district to define what competency is and how to measure it. All school districts and charter schools would have to approve a policy by 2012.
Sponsor Sen. Chris Romer (D-Denver) said he wants to make sure their graduates can perform and be safe on the job and in daily life by speaking and understanding English.
"This bill is very simple in its concepts. What this bill says is if you're going to get a diploma in Colorado, you need to be competent in the English language," said Romer, the sponsor of Senate Bill 73. "The public is really yearning for a thoughtful conversation about assimilation, not just immigration."
Romer said English competency isn't as high a standard as English proficiency, under the definitions of the Colorado Student Assessment Program (CSAP), the standardized tests given to students each year.
Sen. Ron Tupa (D-Boulder) said he wished the bill set a minimum standard for competency. Romer said schools should be given some time to experiment with what works best.
"If we're going to pass public policy, we need to fund our mandates," said Sen. Sue Windels (D-Arvada), the head of the Senate Education Committee. "This is going to end up being just another unfunded mandate on school districts."
The bill is scheduled for final approval later this week.
(The Associated Press contributed to this report. Copyright KUSA*TV, All Rights Reserved.)