English-only language policies and teaching practices have traditionally dominated ELT, but there is evidence that things are changing towards more multilingual approaches. In this chapter, the tensions and ideologies concerning monolingualism and the prevalence of English-only teaching practices in ELT are reviewed before moving on to the more recent multilingual developments and approaches which foster multilingual inclusion and leverage learners’ multilingual resources in the language classroom. In this kind of ELT evolving landscape, the role and concept of “English” are reconsidered so as to align with a more diverse and inclusive approach to ELT, an English as a Lingua Franca (ELF) approach. Finally, the advantages and predicaments of leveraging multilingualism in ELT are explored and some cautionary notes are made too.