要用到pyttsx庫 https://pypi.python.org/pypi/pyttsx
示例：
#coding:utf-8
import pyttsx
eng1 = pyttsx.init()
eng1.say('Sally sells seashells by the seashore')
eng1.say(u'不知道')
eng1.runAndWait()
eng1.say('Sally sells seashells by the seashore')
eng1.say(u'不知道')
eng1.runAndWait()
多加空格不會有停頓效果