Simplify the following text for a Grade 13 native English-speaking person.
Original: Singapore Telecommunications Limited , commonly abbreviated as SingTel , is a telecommunications company , with a combined mobile subscriber base of 383 million customers from its own operations and regional associates in 25 countries at the end of 2010 increased by 34 percent in one year , making it one of the largest mobile network operator in the world .
Simplified: Singapore Telecommunications Limited commonly abbreviated as SingTel , is a telecommunications company . SingTel has a combined mobile subscriber base of 285 million customers as of December 2009 .