Linnell, J., Porter, F. L., Stone, H., & Chen Wan-Lai. (1992). Can you apologize me? An investigation of speech act performance among non-native speakers of English. Working Papers in Educational Linguistics, 8 (2), 33-53.

Examines the performance of apologies among 20 NNSs of English and 20 NSs. The eight verbal discourse completion tests designed by Cohen and Olshtain were administered on a one-to-one basis. No significant differences were found between NNSs and NSs in six of the eight situations. Explicit apologies, acknowledgments of responsibility and intensifiers were significantly undersupplied by NNSs in two of the situations. NNSs undersupplied an explicit apology and an intensifier in an unintentional insult situation and acknowledging responsibility for forgetting a meeting with a boss. Performance did not correlate with TOEFL scores.