Part I of this article explores instances in Mahler's symphonies where the composer allows the continuity of the musical voice to break and to fall temporarily into silence. It analyses these in terms of seven different categories or compositional strategies – violent strikes, abysmal silence, draining away/falling apart, drowning out, hyperintensity, fragmentation, and strained voices. Part II considers the wider context for this breaking of the voice in literary and philosophical self-critiques of language contemporary with Mahler's work, specifically Austro–German forms of Sprachkritik as in the work of Hugo von Hofmannsthal and Fritz Mauthner, but also extending the parallel in less obvious directions to include Samuel Beckett. Taken together, the two parts of the article thus provide both evidence and historical context for a radical suggestion about Mahler's music, that at the heart of the symphonic is a constant threat of the aphonic – a complete loss of voice. While such moments are rare in Mahler, they might be read as extreme manifestations of the self-consciousness of language to which all his music is subject.