I wrote a simple script to do this using only the open source qpython on android (https://github.com/qpython-android/qpython/releases):
import sys, termios, tty
from androidhelper import Android
print('''
pyspeakchar_qpython - start typing to hear characters
press CTRL-D to quit
''')
droid = Android()
fd = sys.stdin.fileno()
settings = termios.tcgetattr(fd)
try:
tty.setraw(fd)
char = 32
while not char in [42, 30, 3, 4]:
droid.ttsSpeak(chr(char))
char = ord(sys.stdin.read(1))
finally:
termios.tcsetattr(fd, termios.TCSADRAIN, settings)