How do I get the broadcast in English?
HBO Max is playing episodes in Spanish
On what device is this happening?
Identify your Apple TV model - Apple Support
List of AirPlay 2-enabled TVs and devices - Apple
It should default to the device default audio language if that matches a track in the stream.
For AirPlay, that may be a setting on the receiving device, not on the sending device.
To change the current audio language to a different one: Change subtitles or languages for videos in the Apple TV app or iTunes Store - Apple Support
To set the default language for the Apple TV box: Adjust video and audio settings on Apple TV - Apple Support
To set the default language for audio and subtitles on third party AirPlay devices, see the AirPlay settings on those devices.