Register-shifting in poetry denotes the deliberate alternation between different linguistic registers—such as formal, colloquial, archaic, technical, or slang—within a single poem to create contrast, irony, social commentary, or psychological depth; by juxtaposing, for example, bureaucratic jargon with intimate confessions or Shakespearean diction with street vernacular, poets can expose class tensions, explore identity fragmentation, or destabilize reader expectations, as seen in the work of Claudia Rankine or Tony Harrison, where register becomes a tool for both aesthetic innovation and sociopolitical critique.

Register-shifting alternates between formal, colloquial, or technical language levels. Related to speech variety. Reveals speaker complexity or social commentary—track shifts to uncover irony, class tension, or emotional volatility.