就好象北京人说话有自己的基调 (music), 上海人说话又自己的基调(music), 山东人说话有自己的基调(music)。。。
我们要找到美语的基调, which is not just pronounciation, it's intonation, speech music...
Which is still mystery to me. Maybe the only way is to listen to native speakers, then practise, imitate...