This chapter moves beyond principles for intelligibility and how an intelligibility-based classroom should be constructed, to a consideration of which specific aspects of pronunciation and other language features are more important for intelligibility, and which are less important. This makes the recommendations different from the recommendations of the Lingua Franca Core, in which pronunciation and other features were largely either essential or not. The basic principle underlying this chapter’s recommendations is that every feature has aspects that are more important, and less important, and an intelligibility-based approach must be selective at all stages. The chapter first argues for building L2 speakers’ skills in perception as an essential part of intelligibility, before moving on to specific features within three major areas, which are presented as having more and less important aspects: those indirectly related to pronunciation; the word-based features; and the discourse-based features. The indirect features have recommendations for fluency features, for vocabulary, and for orthography, or spelling. Word-based features include segmentals (both vowels and consonants), consonant clusters, and word stress. In discourse-based features, recommendations are provided for rhythm, connected speech, prominence, and tune, or final intonation.