Google held its annual developer conference, dubbed Google IO, this week at its headquarters in Mountain View, California. The company kickstarted the event with keynote presentation on Tuesday morning when it announced a new larger Home Hub smart display, its Android Q update, and a mid-range Pixel 3a and Pixel 3a XL.

But did Google reveal another Pixel smartphone on-stage during the keynote? There has been rampant speculation that the Californian company slyly unveiled the next-generation Pixel 4 during a demo of its improvements to Google Assistant.

Google revealed that its new speech recognition and language understanding models have allowed it to reduce the 100GB of models in the cloud that are currently used to power talkative Google Assistant down to less than half a gigabyte.

Thanks to this seriously impressive diet, the AI that powers Google Assistant can now run locally on your phone. As Google demoed on-stage, that makes the response time from your Assistant much, much faster. It also allows real-time transcription, even when you have no network connection.

Google demoed the technology on-stage using an unnamed handset, disguised in a really boxy plastic case, before confirming that its next-generation Google Assistant will be available first on new Pixel phones later this year.

The case blocks the rear camera (cameras?) but has a small cut-out for the LED flash, which was necessary because one of the demos involved asking Google Assistant to switch-on the flashlight. When the handset was shown from the front, the front-facing cameras appear to be housed in the top left-hand corner of the device, which isn't the same design as you'll find on the Pixel 3.

There appears to be no notch, like the Pixel 3 before it, but if this is the tried and tested Pixel that has filled the shelves of your local Carphone Warehouse for the last seven months, why the chunky, secretive case?

Of course, it's possible the sturdy-looking case is simply to differentiate which devices are running the new pre-release software and are to be used during the Google IO keynote.

That would make sense, and would be a good way to stop devices going walkabout accidentally – surely everyone in Mountain View is packing a Pixel 3, right? But surely a simple sticker or something would have sufficed. Why shield the rear cameras?

The last time we saw a boxy plastic case like this was when Samsung unveiled the pliable screen technology that powers its foldable Galaxy Fold without revealing the final design of the smartphone during its own developer conference last year.

Earlier rumours suggest the Pixel 4 XL will have a dual rear-mounted camera – a first for the Pixel range. Google has always insisted it only needs a single lens to produce the same bokeh-style blur that rivals use dual-camera set-ups to achieve.

If the company sticks with its typical launch schedule, we'll see the new Pixel hardware in early October 2019.