Music and language 1 produce phenomenologically different experiences and require different abilities (for example, playing the violin is not speaking). However, they also share interesting commonalities: Both are formed of structured sequences of auditory events that unfold in time and they rely on the same acoustic parameters (frequency, duration, intensity, and timbre). These similarities have opened the intriguing possibility that musical training, by enhancing sensitivity to aspects that are common to music and language, positively influences language processing (the “cascade” hypothesis). As described below, such transfer effects have indeed been demonstrated from musical training to different levels of language processing. 2 Importantly, however, recent results have shown that musical training also influences cross-modal integration (Paraskevopoulos, Kraneburg, Herholz, Bamidis, & Pantev, 2015) and higher-order cognitive functions such as attention, working memory, short and long-term memory, and executive functions that are of primary importance to processing language (the multi-dimensional hypothesis). As a consequence, a currently debated issue is whether improvements in these cognitive functions are mediating the impact of musical training on language processing. However, as we will argue below, these two interpretations are probably best considered as complementary.