This study examines semantically-parallel discourse markers (YOU KNOW/FIOS AGAD and ANYWAY/CO-DHIÙ) of two languages in contact—Scottish Gaelic and English—as a platform for exploring Auer's (1999) ‘Code-Switching-Language Mixing-Fused Lect’ continuum. Using a corpus of about ten hours of speech of older (50+) Gaelic–English bilinguals, this study demonstrates how the employment of English language discourse markers in important positions and the ensuing salience fading of these discourse markers elucidates movement along Auer's continuum. However, the study then debates how swift language shift and the appearance of ‘new’ speakers of Gaelic defy Auer’s allegation, that contact may only advance, not revert, along the continuum.