Microsoft is facing a proposed class action lawsuit accusing its Teams platform of collecting and analyzing users’ voice data without the consent required under Illinois privacy law.

Five Illinois residents filed the complaint in federal court, claiming Microsoft’s real-time transcription tool captures unique voice characteristics — often called “voiceprints” — during online meetings and uses that information to identify speakers. The plaintiffs argue the practice violates the Illinois Biometric Information Privacy Act, commonly known as BIPA.

The lawsuit centers on Teams’ live transcription feature, which converts speech into text and distinguishes between participants. According to the filing, the software evaluates traits such as pitch, tone, and other vocal markers to create individualized speaker profiles. The plaintiffs say these identifiers qualify as biometric data under state law.

Under BIPA, companies must inform users in writing that their biometric information is being collected, explain the purpose of the collection, disclose how long the data will be stored, and obtain written permission before capturing it. The Illinois residents claim Microsoft failed to meet those requirements.

They allege users were never clearly told their voiceprints could be recorded or stored during meetings and were not asked to provide written consent.

The complaint traces the issue to the rollout of Teams’ automated transcription capability in 2021. That system relies on a process known as diarization, which separates and labels different speakers in a conversation. Plaintiffs argue this method effectively creates biometric identifiers comparable to fingerprints or facial recognition data.

The suit also claims Microsoft can connect those voice profiles to specific individuals, either through their Microsoft accounts or through names entered when joining meetings, making the data personally identifiable.

Attorneys for the group say the alleged violations are ongoing, asserting that Microsoft continues to operate the transcription feature without implementing the notice and consent measures required by Illinois law.

The plaintiffs further contend that Microsoft’s public privacy disclosures do not explicitly state that voiceprints are generated or stored. They argue the company references general speech technology but does not clearly inform users that biometric identifiers may be collected during live transcription.

The lawsuit seeks to certify a class of Illinois residents whose voice data was captured through Teams’ transcription services dating back to March 2021.

If successful, the case could expose Microsoft to significant financial penalties. BIPA allows individuals to seek either actual damages or $1,000 for each negligent violation. Alleged reckless or intentional violations can raise damages to $5,000 per instance, which can add up quickly in large-scale class actions.

Biometric privacy lawsuits have become more common in recent years as voice analysis and artificial intelligence tools spread across consumer and workplace technologies. Courts in Illinois have seen similar claims against major tech companies over voice assistants and other speech-based services.

Court records show the case, Basich et al. v. Microsoft Corp., was filed in the U.S. District Court for the Western District of Washington. Microsoft representatives and attorneys for the plaintiffs had not issued public statements at the time of publication.

The outcome could influence how companies handle speech recognition and transcription features, especially when serving users in states with strict biometric privacy protections.