Multi-word expressions are formulaic language universals with arbitrary and idiosyncratic collocations. Their usage and mastery are required of learners of a second language in achieving naturalness. However, despite the importance of multi-word expressions to mastering a second language, their syntactic architecture and colligational possibilities have received little attention in English language teaching (ELT). This study examined lexical bundles, a type of multi-word expressions, to understand their structure and co-occurrence possibilities with other syntactic elements. It was aided by an automated frequency-driven approach using two corpora, the British component of the British National Corpus -- a first language (L1) corpus -- and a purpose-built Nigerian Media Discourse corpus -- a second language (L2) corpus. Two items of lexical analysis software were used to extract three-word lexical bundles with a minimum of 50 frequencies per corpus. The syntactic structures of the identified lexical bundles were determined, and their in-corpus usages were analysed for their colligational characteristics. Results showed that both corpora had instances of general and genre-specific lexical bundles (LBs) with varying frequencies. Five categories of lexical bundles with different structural patterns and peculiar colligational characteristics were identified in the study. Since lexical bundles are more frequently found in both L1-L2 texts, mastering how they are used will further enhance the teaching of English as a second language. The teaching of lexical bundles as a multi-word expression is therefore recommended in ELT as a way of enhancing learners' proficiency and naturalness in English.