外國人在學習華語時，一開始最感困難的往往是聲調的學習。而因學習者母語的不同，他們所面臨的聲調學習難點也不同。在課室教學時，往往因為時間有限，老師們很難針對每位學生個別的聲調錯誤進行糾正，並且都能讓他們有充分的時間練習。因此，學習者課後若仍不能做正確、有效的練習，勢必無法習得聲調的正確發音。 現今隨著科技的進步，許多人致力於研發特殊的電腦軟體，讓學習者可以得到適性化的聲調教學與練習。至今，雖已陸續有相關產品問世，但產品的功能都尚有改善的空間，因此相關研究仍持續在進行中。本文將介紹由MIT、工業技術研究院以及國立台灣師範大學所合作的一項有關「自動化華語聲調錯誤偵測系統」的研究。此研究所使用的群聚分析演算法，可針對大量學習者或個別學習者的口說語料進行聲調模式分析，讓研究者能確切掌握學習者在發各種聲調時，錯誤的型態為何。本研究除了可提供聲調研究者一種較為客觀的、量化分析語音語料的參考模式，亦可作為日後研發電腦輔助華語聲調教學系統的基礎。

Mandarin tones are usually the most difficult part for beginning-level students of Mandarin. Students of different countries have different difficulties in learning Mandarin tones. Due to the limited time in the class, teachers can hardly correct the tonal errors of every single student and give the students enough time for practicing pronunciation. As a result, it is very important for students to do lots of effective exercises to practice the pronunciation of Mandarin tones after class. Nowadays, as the technology advances, many people dedicate themselves to developing specific computer software to support teaching or providing adaptive pronunciation-exercises for students. Although many products are available to date, their functions can still be improved. Accordingly, researches in this field are ongoing. In this article, we introduce a research on an automatic Mandarin tonal error-detection system, which is carried out together by MIT, ITRI in Taiwan, and National Taiwan Normal University. Based on cluster analysis, the system can analyze the tonal patterns in speech corpora of many as well as individual students, so that researchers can precisely catch students' tonal error-patterns. The current research provides not only a quantitative and more objective approach for analyzing speech corpora, but also a basis for developing a computer-assisted system for teaching Mandarin tones.