How wifi/bluetooth speaker can get audio data? As I said in title? How a wifi/bluetooth speaker can get audio data from your device such as phone or PC?
I have an bluetooth speaker and any sound from my phone is sent to that speaker - How they can do that.
Even with wifispeaker, I see that some must run with a program, but some doesn't. Just turn on speaker, connect to your device and you can stream any sound to it.

Thank you
This page on the Bluetooth specification website very quickly descends into technobabble, but the Advanced Audio Distribution Profile is how audio is distributed, or sent, from a Bluetooth audio transmitter (such as iPhone or iPod) to a Bluetooth audio receiver (such as headphones or a stand-alone speaker).

I am not sure how technical of an answer you are looking for, but the page linked above goes into much more detail.