Frontmatter -- Contents -- Introduction -- What Is Intra-individual Variation in Language? -- Part I: Phonetic-phonological dimension -- Everyone Is Different, So Everyone Is the Same - Intra-individual Variation in Second Language Acquisition -- Situational Effects on Intra-individual Variation in German - Reflexes of Middle High German ei in Austrian Speech Repertoires -- Linguistic, Social, and Individual Factors Constraining Variation in Spoken Swiss Standard German -- Part II: Syntactic-morphological dimension -- Intra-individual Variation in Nominal Inflection: Analyses of Directly Elicited Data of the Bavarian Linguistic Atlas -- Intra-individual Variation in Morphosyntax: A Constraint-based Perspective -- Inter- and Intra-individual Variation in Luxembourgish. A Quantitative Analysis of Crowd-sourced Speech Data -- Part III: Historical dimension -- Of Zibele and Bölle: Patterns of Language Variation in the Swiss Language Island New Glarus (North America) -- Intra-individual Variation in Nineteenth-century Private Letters -- Intra-individual Variation from a Historical Perspective: Towards a Usage-based Model of Constructional Change and Variation -- How many Natives with how many Systems? Intra-individual Variation and the Threshold of Multilingualism in Standard German Speakers -- Index