本論文利用語料庫來檢視以英語爲母語的人士如何在現實生活中表示感激。本論文使用兩個著名的口語語料庫，一是密西根學術口語語料庫(Michigan Corpus of Academic Spoken English, or MICASE)，以及英國國家語料庫的口語部分British National Corpus (BNC, the spoken part)。這兩個口語語料庫都包括了各種類型的情境和說話者，與各種不同形式的互動。本文以質性與量性的方式分析以英語爲母語的人士在各種情境中表達感激的方式，並將感激用語分爲六大類。分析結果顯示以英語爲母語的人士最常使用thanks和thank you兩種感激用語。另外，研究成果亦歸納出thanks和thank you的各種不同的功用。例如，他們可以用於表示禮貌，回覆別人的感激，回絕他人的贈與或邀請，以及當作是對話的結束語，這類的用法多出現在BNC語料庫。MICASE語料庫則有較多的appreciate用法，感謝第三者，以及在正式演講場合所使用的較爲正式的感謝用語。對外語學習者而言，表達感激的方式就像其他語言行爲一樣需要加強學習。尤其要學習在適當的時間與情境下，表達適宜的感激方式。

The present study takes a corpus-based approach to investigate the speech act of thanking. Two well-known spoken corpora MICASE and BNC (the spoken part) were used for quantitative and qualitative analysis. Six major categories were identified: (a) thanking, (b) appreciation, (c) non-gratitude, (d) combinations, (e) thanking a 3(superscript rd) person, and (f) formal speech. The results of the study indicate that the thanking strategy constituted the majority of the coded expressions; nevertheless, the second most frequent strategy is the non-gratitude strategy, which performs the illocutionary functions of relief, rejection of an offer, politeness, greetings, and conversation endings. Results also revealed that thank you is much more frequently used than thanks. In addition, data from MICASE show more varieties of strategies than BNC, particularly the more formal strategies such as appreciation, thanking a 3(superscript rd) person, and formal speech whereas BNC contains much more instances of the non-gratitude strategy than MICASE, reflecting register differences of the two corpora. In sum, the wide variety of thanking strategies, the numerous formulaic linguistic realizations, and the expected appropriate responses when being thanked, as shown from the corpora, suggest potential problems the speech act of thanking poses for second language learners.