If you're using Briefcase 0.3.10 or newer (which uses Chaquopy to support Python on Android), then you could use the Chaquopy Python API to play audio files using SoundPool.
For example, the code from this answer could be written in Python as follows:
from android.media import AudioManager, SoundPool
from os.path import dirname, join
soundPool = SoundPool(5, AudioManager.STREAM_MUSIC, 0)
soundId = soundPool.load(join(dirname(__file__), "filename.mp3"), 1)
soundPool.play(soundId, 1, 1, 0, 0, 1)
This will play the file "filename.mp3" from the same directory as the Python source file.