Throughout the book, our discussions have mainly idealized a situation in which an L3 would be the same for all, taking the sequential bilingual (adult L2 learner) who then seeks to acquire an additional language in adulthood as the point of reference. As you will recall from Section 1.3 in Chapter 1, L3/Ln learners can come in various shapes and sizes. Numerically and chronologically, a third language is quite simple to determine, as simple as counting 1, 2 and 3 (see Hammarberg, 2010, 2018, for a more nuanced discussion). However, this does not mean that all L3s are the same as relates to the application of the models we have discussed, much less the patterns of transfer that we might be able to expect.