Two different routes of processing are assumed to be available for morphologically complex words (Pinker, 1991). Common, frequent forms of words are thought to be stored as whole word forms for quick access, involving Wernicke's area and adjacent regions in the left temporal lobe. Infrequent or previously not encountered forms, on the other hand, can be decomposed into stem and affixes to access the stem meaning. In other words, we can understand an incorrect form like *springde *'runned' by decomposing the word into the stem stem and spring+de 'run+PST.' Decomposition, however, involves the 'dorsal route' for grammatical processing (Friederici, 2017), in particular the posterior portion of Broca's area. This processing is likely to be what is reflected in the ERP effect for misapplication of a regular grammatical suffix on an irregular stem, as in *spring+de *'runn+ed': a left anterior negativity (LAN) (Schremm, Novén, Horne, & Roll, 2019). Suffixes that have been incorrectly cued by the wrong word accent in pseudowords with real suffixes like kvup+ar 'kvup+PL' produce a LAN, indicating that an abstract rule associating tone and suffix might be at play (Söderström, Horne, & Roll, 2017). In fact, just like stem-suffix processing in general, tone-suffix association seems to be represented in two possible routes in the brain. Evidence for dual route representation of word accents comes from correlations between cortical thickness and Swedish speakers' capacity for processing their own native language. Thus, native speakers with thicker cortex in Wernicke's area and the mid and ventral anterior temporal lobe process the word accent-suffix associations quicker in frequent real words than speakers with thinner cortex, suggesting that strong whole form representations are important for real words. Conversely, native speakers with thicker cortex in the posterior portion of Broca's area are quicker to process word accent-suffix association as an abstract rule in pseudowords with real stems (Schremm, Novén, Horne, Söderström, van Westen, & Roll, 2018; Novén, Schremm, Horne, & Roll, 2020).