汉语拼音是中文的语音系统。

Hanyu Pinyin is the official Chinese phonetic transcription system.

而每个汉字都由固定的音调构成。如果音调错了，那么意思也就完全变了。
Every Chinese character is pronounced a single syllable. If the tone is wrong, the meaning is changed right away.

普通话有四个基本的声调，每个声调都有其对应的声调符号（如 ā á ǎ à ）。

Mandarin has four basic tones. Each one is indicated by a tone mark, e.g., ā á ǎ à

很多初学者都难以准确掌握第三声的发音, 这里有个小贴士可以帮助你改善。

More beginners cannot pronounce the 3rd tone exactly. Here is a quick tip to help you improve your pronunciation.

http://www.youtube.com/watch?v=3rs8jgVS_ZM

希望这个小贴士对你的汉语学习有所帮助。谢谢！

Hopefully this tip helps you learn Chinese. Thank you!