In Chapter 6, Rosa Rodriguez-Garrido and Albert Pellicer provide an account of issues affecting students who have already acquired two or more languages and are learning an additional one. They start discussing whether using a shared non-native language (English) as a medium in learning a third (L3) or fourth (L4) language assists the way students process a new language at the early stages of acquisition. Through qualitative and quantitative research, they evaluate plurilingual learners’ expectations and perceptions on acquiring an additional language through a non-native one. They estimate from the results of a student questionnaire and later interview whether the use of English can be applied as a tool of shared culture to facilitate cultural translation and word acquisition at the early stages of L3 or L4 learning. They also consider the extent to which language background diversity in the modern languages classroom can support teaching strategies addressing multilingualism and improve standards by taking into account individual differences and further enable every student to succeed as a language learner.