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Microsoft is quietly building its own voice AI stack, and the latest addition is MAI-Realtime, a bidirectional voice model currently in preview that the company says will deliver more natural interactions across multiple languages and tool integrations.
Bidirectional voice means the model can handle both speaking and listening simultaneously, rather than taking turns like a walkie-talkie. The model processes audio in real time, going both directions at once, which is what makes voice feel genuinely conversational rather than robotic.
MAI-Realtime is currently in an internal preview phase, meaning Microsoft hasn’t opened it to public testing or released performance benchmarks yet. What the company has confirmed is that the model is designed to feel more natural, support multiple languages, and work alongside tools, which in Microsoft’s ecosystem likely means integration with Copilot and the broader suite of productivity applications.
MAI-Realtime doesn’t exist in isolation. Microsoft has been assembling a full voice AI stack under the MAI (Microsoft AI) umbrella.
MAI-Voice-1 was first previewed in August 2025 and then expanded in April 2026. That model handles expressive text-to-speech generation and can produce a full minute of audio in under one second using a single GPU. MAI-Voice-1 has already been integrated into Copilot features across multiple Microsoft applications. Alongside that, Microsoft introduced MAI-Transcribe-1, a speech recognition model that handles 25 languages.
Put the three together, MAI-Transcribe-1 for listening, MAI-Voice-1 for speaking, and MAI-Realtime for full bidirectional conversation, and you have a vertically integrated voice AI stack that Microsoft owns end to end.
When Microsoft uses OpenAI’s voice capabilities, it pays for inference, it’s subject to OpenAI’s pricing decisions, and it doesn’t control the roadmap. Building proprietary models changes that calculus entirely.
OpenAI released its own real-time voice API in late 2024, and Google has been pushing Gemini’s multimodal capabilities, which include audio.
If MAI-Realtime gets folded into Copilot for Microsoft 365, it would reach enterprise users across Word, Excel, Teams, and Outlook.
What to watch: whether MAI-Realtime moves from internal preview to public developer access, how quickly it gets integrated into Copilot’s existing voice features, and whether Microsoft starts publishing benchmark comparisons against OpenAI’s real-time voice API.
Disclosure: This article was edited by Editorial Team. For more information on how we create and review content, see our Editorial Policy.
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