This study examines the idiolect of Сашко – a hyper-multilingual global nomad whose language repertoire draws on forty languages, ten of which he speaks with native or native-like proficiency. By analyzing grammatical and lexical features typifying Сашко’s translanguaging practices (code-switches, code-borrowings, and code-mixes), as documented in the corpus of reflexive notes that span the last twenty-five years, the author designs Сашко’s translanguaged grammar. Instead of being a passive additive pluralization of separated, autonomous, and static monolects, Сашко’s grammar emerges as a deeply orchestrated, unitary, and dynamic strategy. From Сашко’s perspective, this grammar constitutes a tool to express his rebellious and defiant identity; a tool that – while aiming to combat Western mono-culturalisms, compartmented multilingualisms, and nationalisms – ultimately leads to Сашко’s linguistic and cultural homelessness. This paper – the first in the series of three articles – is dedicated to methodological issues: the frameworks that are adopted in the different parts of the study, the method with which the description and analysis of Сашко’s idiolect is developed, and the corpus that underlies the empirical research of Сашко-lect.