Investors from venture capital firms like Andreessen Horowitz and Greylock Partners said on Monday that they had invested $21 million in Cresta, a call center technology startup co-founded by Sebastian Thrun, a high-profile Silicon Valley executive who founded Google’s so-called X moonshot factory and online education company Udacity.

Cresta’s software analyzes a corporate client’s call center transcripts to learn which phrases or words top salespeople have used that ultimately led to successful sales. Other agents are then prompted to use that language when they field customer calls, in an effort to increase sales.

“We built software that provides real-time prompts, like what to say during a conversation to help guide them,” said Cresta CEO Zayd Enam.

For example, a call-center agent for a home improvement store who gets a call about kitchen sinks may see a prompt to ask about kitchen tiles. The goal is to prod agents to ask more questions that ultimately lead customers to buy products that they wouldn’t otherwise have.

Enam’s idea for Cresta started with his PhD project that involved applying breakthroughs in computers understanding language to reduce some of the repetition of modern corporate work. Although his research originally focused on tasks like creating automated answers to emails, Thrun, who was Enam’s PhD advisor at Stanford University, suggested that it should be focused on more specific tasks that could be more applicable to business problems like sales.

“When you have this broad vision you can’t do everything—you have to narrow it down,” Thrun said. “You have to find the [business] case where you can operationalize it, make it happen, and effectively make money.” 

Thrun is chairman of Cresta, with no daily operational role. He is currently CEO of KittyHawk, a company backed by Google co-founder Larry Page that is trying to develop flying vehicles.

Cresta’s software underscores recent advances in natural language processing (NLP) that have led to a number of companies applying the technology to corporate call centers. As Gartner vice president of research Olive Huang previously told Fortune, while computers still struggle to always understand human voices, they are still good enough for companies to use in their corporate call centers, reducing the need to hire as many call center staff.

Now, tech companies like Google, Amazon, and communications software firm Twilio have noticed the trend and have all created their own A.I. technologies for call centers. In November, Salesforce said that it plans to debut its own A.I.-powered customer-service tool to assist call center workers handing customer calls.

Big tech companies make for serious competition to Cresta, which has only 30 employees. But, lead investor Ben Horowitz, a venture capitalist with Andreessen Horowitz, said Cresta’s software is powerful enough to stand out in the crowded field. Horowitz is betting that customers will be swayed by the company’s product rather than be captivated by the “positioning and branding” of larger tech companies. 

“I would rather have more money than the comfort of knowing I bought it from Marc Benioff,” Horowitz said about the software’s presumed effectiveness compared to competing call center software sold by Salesforce.

Some of Cresta’s other investors include Sun Microsystems co-founder Andy Bechtolsheim, Mark Leslie, and Aviv “Vivi” Nevo.