Live Rewind shows the last 15 seconds of speech as text when you double press the Digital Crown. It also plays a chime from the speaker, even with the watch on silent or headphones connected, and puts a full-screen animation and a microphone indicator on the display, according to Apple's explanation of the feature. It doesn't keep transcribing after that. The snippet disappears about 30 seconds after the display dims unless you save it.
Siri Recap listens through the day and takes notes on your conversations. Apple says it won't attribute anything to an individual speaker, leaves out financial data, government identifiers and authentication data, and deletes unsaved summaries after seven days. It's opt-in, and you can set it to listen only at work or never at night. The iPhone transcribes and condenses what the watch hears inside its Secure Exclave, but Apple's support document names cloud-based AI models too, and Private Cloud Compute writes the final summary. Apple's own advice is to "consider those around you where conversations might be private or sensitive." Neither feature reaches the EU at launch.