This chapter explores the extent to which phonetic environment, lexical frequency, and social factors interact and incite or impede sound change over the lifespan of the individual. The corpus consists of sociolinguistic interviews with 20 panel speakers of Swabian, an Alemannic dialect spoken in southwestern Germany, from two different communities, Stuttgart and Schwäbisch Gmünd, first recorded in 1982 and again in 2017. We investigate the modern standard German diphthong [ai] which evolved from two different Middle High German (MHG) phonemes, /i:/ and /ei/. We use generalised additive mixed-effect models to investigate to what extent F1/F2 trajectories in the vowel space differ in lemmata originating from the two MHG phonemes based on the Total Euclidean Distance Squared (TEDS). In addition to voicing effects, we find that an interaction between community, lexical frequency, and indexicalities of Swabian identity affects the degree to which the two diphthongs are merging, or at least becoming more similar to one another, within the lifespan of one generation. By analysing intra-speaker trajectories, we show how sound change is governed by the intricate interplay between structural factors and individual speaker notions of language ideology, social meaning, and dialect identity.