Open English, the online English language school, has just raised a staggering $43 million in Series C funding led by Insight Venture Partners.

The Miami-based start-up offers a 12-month online program in which students, who pay tuition, have 24/7 access to live teachers and resources online. Recently, the company has seen massive growth in Latin America.

“I think our investors are very excited--as are we--about the growing middle class in Latin America,” says Andrés Moreno, CEO and co-founder of Open English. “For this class to continue its ascendance, there are a lot of ... key skills that they will need to navigate this world effectively--English and education are a really big part of that.”

Launched in 2006, the company’s classes typically have a three-to-one student-to-teacher ratio, in which students can interact with their fellow students and instructors in a video-chat environment. Students also have access to personal advisors who can help them track their progress toward fluency.

“We see our model as more effective and convenient to our target market,” says Moreno. “We want to continue to invest in our product and service with these funds to make sure it is a superior way to learn English.”

With offices in Miami, Caracas, Bogotá, São Paulo, and Panamá, the company services 20 countries and more than 50,000 students. Moreno says he hopes to increase that number to 80,000 by the end of 2012.

He adds that he also will use the money to boost advertising and marketing campaigns.

“Investors are looking for companies that need money to grow more quickly, not to prove that their product works. And that’s where we are,” says Moreno.

Open English is one of a series of education start-ups that has seen investment recently, including Codecademy, which raised $10 million, and Khan Academy, which raised $5 million.