As stated by Professor Brinton, most publications dealing with the field of English historical linguistics are focused on "linguistic levels of change - phonological change, morphological change, syntactic change, and semantic change" (p. 1) while those dealing with the history of English are mainly "organized chronologically" (p. 1), with chapters devoted to specific periods (i.e. Old English, Middle English, Early Modern English and Late Modern English). Chapter 6, "Approaches to Grammaticalization and Lexicalization" (pp. 131-157) by Lieselotte Brems (Universitè de Liège) and Sebastian Hoffmann (Universität Trier), explains the concepts and utility of "grammaticalization" and "lexicalization" in English diachrony. The second case study is connected with the processes of lexical and grammatical change as they apply to comment clauses typically found in spoken discourse ( I you know, I guess, I mean, I think, you know, you see i ...), as well as the three main processes affecting comment clauses and discourse markers: grammaticalization, lexicalization, and pragmaticalization. Corpus linguistics and statistics with R: Introduction to quantitative methods in linguistics. [Extracted from the article]