This document on “Tough Questions” has been written for education practitioners who are experienced in their field, but who have come up against some tough obstacles to implementing MTBMLE programs in their context; these are the people who provided the questions in the first place. The eight questions addressed here are: • How can mother tongue–based MLE be carried out in classrooms where three or more local languages are represented as mother tongues? • What is the most effective approach to transition to the use of a second language as medium of instruction when classroom policy and practice has used the learner’s home language/first language in the early primary years? Which school year is best for implementing this transition? • What can be done in contexts where teachers have inadequate oral fluency or literacy skills in one or more of the languages being used in the program? • How can pilot MTB-MLE programs be successfully scaled up? • How can instructional materials and supplementary reading materials be effectively developed for target populations speaking multiple dialects? • When the orthography of the local language is not yet standardized or requires further review in order to adequately represent the linguistic features of the language, how should this challenge be handled in the program? • How can informal and non-formal learning opportunities in the mother tongue best support or supplement school settings, particularly when the formal school system is unable to serve as a venue for mother tongue–based multilingual education? • What approaches have been proven effective for managing the use of two or more languages in a bilingual/multilingual curriculum? These eight questions have been addressed by experienced MLE consultants working around the world, in a range of program conditions. The answers aim to provide alternatives for meeting the challenges embodied in the questions in practical, credible ways. It is hoped that these responses will help make a challenging job just a bit easier.