International teaching assistants (ITAs) often receive specialized training because their spoken English is not easily comprehensible. Lack of comprehensibility may be influenced by grammatical issues (Tyler, 1994), incorrect or inadequate discourse structure (Tyler, 1992; Williams, 1992), or aspects of their pronunciation, such as unclear sentence focus (Hahn, 2004) or intonation (Pickering, 2001; Wennerstrom, 1998). Problems with comprehensibility may be compounded by ITAs having learned English through formal, written models. However, we do not know how ITAs change written text into an oral lecture, nor how their strategies differ from those of native teaching assistants (NTAs) doing the same task. This paper reports results of such a study. We video-recorded three different groups of engineering TAs (American, Chinese, and Indian) presenting information from a textbook passage. Each TA was asked to read the same passage taken from a first-year college physics textbook, and then to teach the content in spoken English. Presentations were transcribed and analyzed using a Systemic Functional Linguistics approach (Halliday, 1994; Halliday & Matthiessen, 2004; Mohan, 2007). Changes made by each group of TAs from the written to the spoken language were compared, and the strategies used by each group to mark their changes from written into spoken language were examined. The results provide a baseline measure of strategies for turning written into spoken texts used by the TAs in our study. Implications for TA training are discussed.