Google’s NotebookLM appears to be preparing another round of upgrades for its Audio and Video Overviews. In recent teasers, Google pointed to new narration options, including a British English voice that is currently framed as arriving in 2026, expanding the set of voices users can pick for generated overviews.
Ok, before we actually take a much needed respite for the holidays, we wanted to check... Did anyone notice the easter egg in our newest Featured Notebook? No? Here's a wee snippet:
— NotebookLM (@NotebookLM) December 22, 2025
(We hope you'll be absolutely chuffed! Coming soon in 2026.) pic.twitter.com/df0vqJFX85
Alongside that, strings and UI references in a recent NotebookLM build point to a new “Lecture” format for Audio Overviews, positioned next to Deep Dive, Brief, Critique, and Debate.
BREAKING 🚨: Google might be working on a "Lecture" format for Audio Overviews on NotebookLM. Lectures would have a single host narration and could last for 30 minutes.
— TestingCatalog News 🗞 (@testingcatalog) December 23, 2025
Exclusive Notebook with TestingCatalog Lecture sample in the post below.
Listening time 👀 pic.twitter.com/kr4DolMtAR
The description labels it as a comprehensive AI-generated lecture. When paired with the “Long” length option, the mode appears designed to produce an audio session of roughly 30 minutes, delivered by a single host speaking continuously in a lecture-style monologue, with more emphasis on explaining and connecting material across the provided sources.
A language selector also seems tied to this mode, suggesting lectures could be produced in different languages depending on the user’s settings.
If Google ships it, Lecture would likely live inside the Audio Overview format picker and follow the same workflow as existing modes: users upload or select a source set, choose the format, then generate audio. The main audience is students, researchers, and professionals who want a listenable pass over dense source packs, for example:
- Exam prep
- Briefing before meetings
- Reviewing internal documentation while commuting
We have generated one sample lecture using TestingCatalog sources to show the pacing and structure, but the feature is not publicly exposed today, so launch timing and final availability remain unclear.
NotebookLM is Google’s AI-powered research and study tool that lets you collect documents, links, and notes into a single notebook, then ask questions and generate structured outputs grounded in those sources, such as summaries, outlines, and Audio or Video Overviews designed to help users review material faster.
