Google's latest iPhone application that allows users to perform Web searches via voice recognition has been said to explicitly break Apple's "App Store" rules since the Google team made use of an undocumented API which shouldn't normally be used by iPhone developers, Google spokesman said earlier today in a statement.

Launched just shortly over a week ago on the iPhone application store, this innovative program by the Google developer team allows iPhone users to search the Web through voice recognition and has encountered overall positive reviews so far thanks to its ability to accurately parse complex sentences on the first try.

The application can recognize when a user approaches his/her mouth to the device microphone to specify a search query without the need for pressing any buttons at all, and works by registering a compressed audio file, sending it to Google servers that parse the most likely meaning of the query, and then return the search results back to the user, all in a matter of a few seconds.

Free to download and use, the release of this piece of software on the iPhone App Store was however delayed from Friday to the following Monday by Apple, for no apparent reason. Now, however, it has become clear that the most likely reason for such a delay is the breach of the iPhone SDK terms and conditions by Google.

The Google developer team has in fact admitted using an undocumented API in writing the application, explicitely going against the terms that programmers have to agree to when downloading and using iPhone's software developer kit. The reason for such a limitation, explains MacWorld, is quite simply that those libraries are still in testing phase and might therefore cause the application to crash unexpectedly as the libraries get updated.

In particular, the Google team had to resort to using an undocumented API to enable the software to automatically detect when the user is approaching his or her mouth to the device and specifying a search query, a function that is provided by the built-in proximity sensor.

This is not the first time that Google blatantly breaks the terms and conditions for

iPhone applications: in an analogous case that took place earlier this week, the iPhone team updated its OS version to 2.2 and included Google software that, yet again, makes use of undocumented proximity sensor API to switch off the touchscreen control whenever users hold the phone to their face to make a call.

What is maybe most surprising in this story is that Apple, traditionally very strict in enforcing its own terms and deciding which applications get to be featured in its store, eventually decided to close one eye and allow Google's voice recognition and search tool to be downloaded through its official channels. As TechSpot noted, now that Google has come clean Apple might choose to enforce the rules of the iPhone SDK and force the search giant to rewrite the application, although nothing so far leads to believe that anything like this is going to happen.

Should Apple decide not to intervene, though, the risk the Cupertino-based company is running is to make its entire developer community aware of the fact that "not all programmers are treated equal", which might end up negatively affect the number and quality of iPhone applications submitted to the App Store in the near future. Some critics of Apple policies already say the company is very arbitrary in deciding which applications get to be featured on the store and tends to penalize all the software that is directly competing with other existing Apple-branded iPhone programs.

Detractors of the App Store policies include CNET's Tom Krazit, who writes:

"the App Store approval process doesn't make sense: applications that don't violate any public guidelines are rejected for nebulous reasons, while applications that violate the rules sail through. Last week, Apple rejected an update to an application called CastCatcher that had already been approved three times, and then this week, it approved the update without requiring any substantial changes, according to the developer".

What is an even more disconcerting consequence — continues Krazit — is that, should such policies remain unchanged, those who play by the rules soon won't be able to compete with the industry titans that can afford to break them without consequences at the sole risk of seeing errors and crashes on their products as firmware and APIs get updated by Apple.