Research on generic structures of acknowledgements in dissertations has gradually drawn attention in various contexts. However, there is relatively scant research on the ways in which acknowledgements are written by authors with mutually similar cultural backgrounds but in two different academic environments and language contexts. To fill this gap, this study compared 60 PhD dissertation acknowledgements written by Taiwanese postgraduates in Taiwan, an EFL context, with another 60 written by Taiwanese scholars who obtained their doctorates in the United States, an ESL context. The focus was on the generic structures and linguistic features of the writing styles of the two groups. The study aimed to investigate whether divergences existed in the two different academic and language settings, but with the writers sharing the same cultural and language background. If such divergences did exist, the likely causes would be explored. The results revealed that firstly, the participants in both contexts generally followed a three-tier structure when writing their dissertation acknowledgements, namely, reflecting, thanking, and announcing moves. However, academic conventions, institutional preferences and the language context, together with socio-cultural factors, affected their construction of moves/steps and their choice of linguistic elements. It was found that the rhetorical language in both corpora was relatively direct, emotional and precise.