Multi-word combinations are crucial for the production of various discourse types as well as for the construction of a credible and persuasive academic persona. This study investigates the frequency, structure, and function of the most frequently occurring 4-lexical bundles in writings from the field of linguistics. Following Biber et al.'s (1999) corpus driven-approach, a total of 87 and 113 of lexical bundles were identified in expert and student writing, respectively. Findings revealed substantial differences in the frequency distribution of lexical bundles across the structural categories. More precisely, the study indicated that the student cohort relied heavily on clausal bundles. Expert writers, on the other hand, showed increased use of phrasal bundles, which are considered indicative of proficient academic writing. In terms of function, the analysis showed a preferential attachment to certain lexical bundle functions, with text-oriented bundles occurring significantly in student writing as opposed to research-oriented bundles which were predominantly used in expert writing. These functional differences also suggest diachronic changes in experts' use of these word sequences due to the discipline's discursive demands.