Program I wrote with 1st grade son, started much simpler and grew to this

animals.py

#!/usr/bin/python
# .
# |-- animals.py
# `-- sounds
#     |-- cat.wav
#     |-- cow.wav
#     |-- dog.wav
#     |-- oops.wav
#     |-- sheep.wav
#     `-- wolf.wav

import os
import sys


def say_animal_sound(animal):
    animal_file = 'sounds/{}.wav'.format(animal)
    animal_play = 'paplay ' + animal_file
    os.system(animal_play)


letters_to_sounds = {'d': 'dog',
                     'c': 'cat',
                     'o': 'cow',
                     'w': 'wolf',
                     's': 'sheep'}


while True:
    letter = sys.stdin.read(1)

    # If the letter is "q", Quit the program.
    if letter in ('q', ''):
        break

    # If the letter is "Enter" key, skip it.
    if letter == '\n':
        continue

    # Look up the animal name from the letter
    # given to us.
    sound = letters_to_sounds.get(letter, 'oops')
    say_animal_sound(sound)