Google NotebookLM is testing a new deep learning “Lecture” mode that lasts 30 minutes.

By developing a new “Lecture” style for its Audio Overviews and a potential British accent option, Google is improving its AI program, NotebookLM.

In an app breakdown, TestingCatalog discovered the new Lecture format, which is very different from the current Audio Overview styles like “Deep Dive” or “Debate.”

Lecture uses a single narrator to provide an ongoing, academic explanation rather than a conversation between two AI hosts. These lectures have a maximum duration of thirty minutes when combined with the “Long” duration setting.

The tone is the main difference. Instead of offering a brief synopsis or a staged discussion, the format is intended to be calm and instructive, linking complicated concepts across a user’s sources. For students and researchers attempting to understand complex information without gazing at a screen, this makes it perfect for prolonged listening, as during a commute.

The fact that TestingCatalog has already produced a whole 30-minute sample indicates that this is not a covert experiment but rather a scheduled fifth mode.

In 2026, Google plans to launch British English narrating voices in addition to the new format. The British expression “you’ll be absolutely chuffed” was used by the corporation to hint at the upgrade on X (previously Twitter).

“Archive 1945,” a Featured Notebook produced in association with The Economist, already offers a sneak peek at this speech technology. The functioning demos indicate that the Lecture edition is being actively prepared for launch, even if it is still in the testing stage and does not yet have an official release date.