Most of the tech world has been genuinely captivated by Apple's (Nasdaq: AAPL) Siri, if you don't count Google's (Nasdaq: GOOG) Android head Andy Rubin or Microsoft's (Nasdaq: MSFT) Windows Phone President Andy Lees, who have both brushed off the threat.

Rubin doesn't "believe that your phone should be an assistant" and that "you shouldn't be communicating with the phone; you should be communicating with somebody on the other side of the phone." Likewise, Lees doesn't believe that talking to your phone is "super useful." Sounds to me like the pair are in denial about having a case of Siri envy.

Behind the scenes, evidence is gathering that (Nasdaq: AMZN) picked up small speech-recognition start-up Yap. The Atlantic uncovered an SEC filing that showed that Yap had merged with a company called Dion Acquisition Sub. A little bit of sleuthing uncovered that Dion is headquartered at a building owned solely by Amazon, which suggests that Amazon used a shell company to quietly pick up the start-up. The filing shows that the deal was finalized in early September.

Amazon will naturally incorporate Yap in some form or fashion into the Kindle lineup, but will it be able to hold its own against Siri? While most are jumping to that conclusion, you need to consider what Yap offered compared to what Siri offered before Apple picked it up.

Yap provided a voice mail transcription service, which was discontinued in late October following the merger. This puts Yap more on par with speech recognition, while Siri's strength is artificial intelligence. Siri's back end utilizes Fool newsletter recommendation Nuance Communications (Nasdaq: NUAN) for recognition after switching from Vlingo, while Siri does the thinking. While on the surface it would seem that Siri and Yap would go head to head, the offerings are entirely different.

Adding voice as an input medium to the Kindle family is a no-brainer, and needs to be done to stay abreast with some of Siri's basic functionality and Google Voice Actions for Android. At least in its current iteration, Yap can't take on Siri directly.

Add to your watchlist to see what it does with Yap. Sign up for a free trial of Motley Fool Stock Advisor to read why Nuance Communications may fit in your portfolio.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.