you're using a computer
the bare minimum of a computer is an electrical signal
that signal is treated as either on or off
on/off is read by a computer as 1/0
1s and 0s are binary
so yes, it's binary
that binary is used to represent printable characters
scratch reads those printable characters as data
scratch uses that data to create a sound
that sound is transmitted over the internet
snap reads the transmission
snap gets printable characters
snap reads those printable characters as data
snap uses that data to recreate the sound