NotebookLM is flirting with long lectures and British accents

As much as we admire NotebookLM, Google isn’t resting on its laurels and continues to tweak the AI app. The latest feature in testing looks to be a new “Lecture” format for Audio Overviews in NotebookLM, and there may also be a British twist on the way.

Instead of two AI hosts chatting things through, Lecture appears to stick to a single narrator delivering a continuous, lecture-style explanation that can run for up to half an hour. According to TestingCatalog, which appears to have enabled the feature in a teardown of the app, the Lecture option shows up alongside existing Audio Overview formats, such as Deep Dive, Brief, Critique, and Debate.

The key difference between these lectures and other versions of NotebookLM Audio Overviews lies in tone and structure. This one’s designed to calmly explain and connect ideas across your sources, rather than summarising quickly or staging a back-and-forth. Paired with the “Long” length setting, it looks built for proper sit-down listening, or at least something you can stick on during your commute to get to grips with a subject.

TestingCatalog has already generated a full 30-minute sample lecture to demonstrate how it works, which suggests this isn’t just a half-finished experiment hidden in the UI. It feels like a deliberate fifth mode, aimed squarely at students, researchers, or anyone trying to grasp dense material without staring at a screen.

There’s also a tangentially related side note here, which British ears in particular will appreciate. NotebookLM has been teasing new narration voices with British English accents planned for 2026, complete with a very knowing “you’ll be absolutely chuffed” nod on X. One of these voices can already be heard in a Featured Notebook called “Archive 1945” that was created in collaboration with The Economist, hinting that the groundwork is already in place.

Since the Lecture addition was spotted in testing and hasn’t yet rolled out, we don’t know when it’ll appear or if it’ll look the same when it does. Still, between a working demo and Google openly teasing new voices, this feels like something that’s being readied in the wings.