Amazon isn't shy about wanting to own as much of the Kindle Fire's software experience as it can, which creates a challenge when implementing voice search -- the company can't just re-skin Google Now and call it a day. The next-quickest alternative is to buy a company wholesale, and TechCrunch has evidence that Amazon may have gone that route through a very stealthy acquisition of Evi, best known for its eponymous personal assistant app. While neither side has publicly commented on the deal, our colleagues have noticed that all of Evi's directors and its company secretary have been replaced by staffers linked to Amazon UK. If it's not an acquisition, there's been at least some loss of autonomy. We don't know exactly what Amazon would be doing should the acquisition prove real, although Evi's Nuance-powered voice assistance for Android and iOS may be enough of a clue in itself -- there's only so many places Amazon can go with such a narrowly focused company.