Within the scope of his PhD studies, he concentrated on the phonology and lexicology of Middle Korean. His disseration "Die lexikologischen und phonologischen Grundlagen der inneren Rekonstruktion im Mittelkoreanischen" (The lexicological and phonological basis for internal reconstruction in Middle Korean) was supervised by Professor Dr. Alexander Vovin (Hawai'i) and awarded in Hamburg, 2008. He has been teaching Middle Korean for several years and is in charge of Korean collection in the faculty library. Besides, he has worked on educational history in Chosŏn. He is also editor of the Korean section of the Hefte für ostasiatische Literatur (iudicium, since issue 2/2005).

• Traulsen, Thorsten et.al. [transl.]: 'Was du mir bedeutest' by Kim Young-ha.
  Hefte für Ostasiatische Literatur No. 2/2005.
• Traulsen, Thorsten: The interaction of segments and suprasegmentals in Late Middle Korean: Its meaning for internal reconstruction. In: Rhee, Sang Jik [Ed.]: The proceedings of the 1st European Conferance on Korean Linguistics (ECKL 1), Seoul: Hankook Publ., 2005. pp. 167-181.
• Traulsen, Thorsten [rev.]: Korean Language in Culture and Society (review).
  Acta Koreana 10 No. 1 (2007): 164-168.

• In search of voice: Reconstruction of voiceness in Proto-Korean. Korean Studies Graduate Students' Convention, London 2005-05-12.
• Consonant skeleton and consonant clusters in Middle Korean: An articulatory account for an old problem. Association for Korean Studies in Europe Conference, Sheffield 2005-07-07
• From Hyangch'al to Han'gŭl. EPEL lecture, Rom 2007-03-16 and 19
• Introduction to Middle Korean. EPEL lecture, Rom 2007-03-23 and 26
• Syllabic structure in Korean Hyangch'al writing. IVth Symposium 'The Idea of Writing', Leiden 2007-05-30
• Chinese Primers in Chosŏn Korea – the Thousand-Character-Classic and beyond. Aspects of diglossia in the medieval Hanmun and Latin cultural spheres, Bochum 2007-08-10
• Chinesisch-Lehrbücher in Chosŏn Korea: der Tausend-Zeichen-Klassiker und weiteres. Mittagsforum der Ostasienwissenschaften, Ruhr-Universität Bochum, 2007-07