A federal judge has decided that a voice misappropriation lawsuit against Google's NotebookLM can move forward in California state court rather than federal court, marking a significant early victory for NPR personality David Greene. The ruling doesn't determine whether Google actually violated Greene's rights, but it does establish that voice imitation claims fall outside copyright law and belong in state courts where right-of-publicity protections apply.

What Is NotebookLM and Why Is This Voice Dispute Happening?

NotebookLM is Google's artificial intelligence product that transforms documents and source materials into conversational podcast-style summaries called "Audio Overviews." Users upload materials, and the tool generates synthetic hosts that discuss the content in a natural, human-sounding way. The AI hosts use pauses, filler words, and vocal mannerisms that make them sound remarkably conversational.

David Greene, a nationally recognized radio and podcast personality who has hosted multiple National Public Radio programs, alleges that NotebookLM's default male AI host, identified as "Charlie," sounds substantially similar to his own voice. Greene claims the synthetic voice reproduces his distinctive sound, tone, cadence, and vocal mannerisms without his authorization. According to his complaint, journalists, former colleagues, and friends began asking whether he had licensed his voice to Google.

Google disputes the allegations, maintaining publicly that the NotebookLM voice is based on a professional voice actor whom the company hired. At this stage of the litigation, the court has not determined which side's account is correct.

Why Did the Judge Send This Case Back to State Court?

Google initially removed the lawsuit from California state court to federal court, arguing that Greene's claims were essentially copyright claims because they involved the alleged copying of Greene's recorded radio and podcast performances. Google contended that federal copyright law should handle the dispute.

However, Judge Charles R. Breyer rejected this reasoning. The judge concluded that Greene's claims focus primarily on the output of Google's AI product, the allegedly unauthorized imitation of Greene's voice and identity, rather than on the input, such as whether Google copied sound recordings to train the model. Since a person's voice and identity are not themselves copyrightable works, the court determined that Google had not established federal copyright jurisdiction.

This distinction between AI inputs and outputs proved crucial. While Google may have used recordings of Greene's performances during AI training, the alleged harm Greene suffered was not simply that Google reproduced his podcast episodes. Instead, Greene alleges that Google created an artificial voice that listeners reasonably associate with him, causing confusion about whether he authorized its use.

What Legal Claims Is Greene Making Against Google?

Greene filed his original complaint in California state court on January 23, 2026, asserting four state-law causes of action that protect his voice, identity, and persona rather than copyrighted works:

• Statutory Right of Publicity: Greene alleges that Google knowingly used his voice or likeness for a commercial purpose without his consent, violating California Civil Code Section 3344.
• Unfair Competition: Greene claims that Google failed to disclose that NotebookLM's male voice was engineered to imitate his distinctive voice, violating California's Business and Professions Code Section 17200.
• Common-Law Right of Publicity: Greene asserts that Google commercially exploited a core attribute of his identity, his distinctive and recognizable voice, without authorization.
• Unjust Enrichment: Greene alleges that Google received commercial benefit by exploiting the value of his voice and professional persona without compensating him.

These claims target personal attributes rather than copyrighted works, which is why the court determined they belong in state court under California's right-of-publicity laws.

How to Understand the Difference Between Voice Imitation and Copyright Infringement

The legal distinction between copying a recording and imitating a voice is becoming increasingly important as AI technology advances. Here are the key differences that courts now recognize:

• Copyright Infringement: Occurs when someone reproduces or distributes a fixed sound recording without permission, such as copying an entire podcast episode or using a recording in a new product.
• Voice Misappropriation: Occurs when someone creates a new synthetic voice that imitates an identifiable person's distinctive vocal characteristics, tone, and mannerisms in a way that causes listeners to associate the voice with that person.
• Training Data vs. Output: Using recordings to train an AI model (input) is legally distinct from creating an AI voice that sounds like a specific person (output), and courts are now treating these as separate legal issues.

Judge Breyer emphasized that it is not enough for a state-law claim merely to involve or reference a copyrighted work. Courts must identify the actual basis of the alleged misappropriation. If the claim protects a person's name, likeness, voice, identity, or persona, the claim may remain outside copyright law and belong in state court.

What Happens Next in the Greene v. Google Case?

The court's July 23, 2026 remand order does not decide whether Google actually copied Greene's recordings, whether NotebookLM's synthetic voice legally misappropriates Greene's identity, or whether Greene will ultimately recover damages. The decision addresses only where the case should be heard, not who should ultimately win.

Now that the case has returned to California state court, the litigation will proceed under state right-of-publicity law. The central question that will likely emerge as the case develops is whether NotebookLM's male host sounds sufficiently like Greene that ordinary listeners may reasonably believe Greene provided the voice or authorized its use. This distinction between a generic synthetic voice and an imitation of an identifiable person will be critical to the outcome.

The case represents an early test of how courts will handle voice imitation claims in the AI era. As AI-generated voices become more sophisticated and lifelike, questions about whether companies can create synthetic voices that resemble famous individuals without permission will likely become more common. The Greene case may establish important precedent for how California courts balance AI innovation against protections for individuals' distinctive voices and identities.