This paper investigated frequencies and functions of focus referential bundles in academic texts. The data were collected from three academic corpora: (i) English academic journal ·articles published by L l researchers; (ii) English academic journal articles by L2 researchers with Chinese language backgrounds; (iii) and English PhD theses written by L2 graduate students in Taiwan. The research data consisted of 1236 research papers, amounting to more than 8 million words. The results showed that the two L2 corpora tended to employ more focus bundles than the LI corpus, suggesting that the L2 writers might have been more ready to validate their arguments in reference to their personal commitments to the certainty of an accompanied proposition. The L2 writers appear to have internalized discourse functions of certain academic 'core' bundles and have the ability to use them like the LI writers. However, they are not as confident as the LI counterparts in using other types of bundles. This distinction might be accountable in terms of the language backgrounds of the writers concerned. Therefore, it is advisable for English teachers to help L2 students acquire conscious knowledge of how focus referential bundles function in academic discourse.