This study investigates potential cross-disciplinary effects on the extent of syntactic complexity and lexical diversity (SC & LD, respectively) in English conference abstracts authored by Egyptian (Arabic L1) researchers in two disciplines: Linguistics and Nuclear Science. The study establishes a native speaker baseline through parallel analysis of British-authored abstracts in the two disciplines under investigation. The data comprises 100 single-authored English conference abstracts, evenly divided over four contrastive categories: Eg(yptian)-Ling(uistics), Eg-N(uclear) Sc(ience), Br(itish)-Ling, and Br-NSc. Using two computational tools, L2 Syntactic Complexity Analyzer (L2SCA) and TEXT INSPECTOR, scores of SC and LD, respectively, have been extracted and managed in MS Excel through some statistical tools. The results have indicated significant and uniform cross-disciplinary effects in both the native and non-native groups in terms of SC, where the Ling abstracts have displayed longer and more complex production units. Furthermore, significant language nativity effects have been observed in terms of SC; English natives have been found to use more subordination, which is characteristic of more mature writing in their L1. Arabic natives, on the other hand, have made greater use of coordination which is the preferred structure-combining operation in their L1. In terms of LD, the native groups have outperformed the non-native groups across both disciplines.