A study compared the topical structure (TS) of Arabic and English in order to determine whether Arab learners of English as a Second Language (ESL) transfer potential differences between Arabic and English in their English writing, or whether they use an altogether different TS indicative of developmental factors. Four sets of data were compared directly: Arabic texts; English texts; English essays by Arab ESL learners; and English essays by non-Arab ESL learners. Results show no significant differences between the TS of Arabic, English, and the English writing of Arab subjects. It is then argued that textual features of expository prose may have masked potential differences in the data considered, and that TS analysis alone is not sufficient for explaining the Arab subjects' deficiencies in developing topics. Contains 29 references. (Author/MSE)