The study of lexical and grammatical patterns in the language that a learner must assimilate is important for pedagogical considerations. Therefore, the linguistic approach in ESP classrooms today is gaining its momentum. Additionally, the adoption of corpus-based language investigation has made the attempts even more accessible; many aspects of the specialised language can be described empirically and systematically. It has been discovered that word and structure frequencies of a specialised corpus are greatly different from a large corpus. They provide insights into the features of the specialised language. Hence, this paper demonstrates the different, yet useful information about a specialised language that can be discerned from the analysis of three types of wordlist; namely, frequency wordlist, keyword list and key-keyword list. The findings inform the features of the specialised language that need to be highlighted in an ESP classroom.