Claude Opus 5 Drifts Into British Spellings, Cites Context as Precedent

ericm272 · reddit · 2026-08-12

A user reports that Claude Opus 5 unexpectedly adopts British English spellings (like behaviour), even when prompted in a clear American context.

Interestingly, if not corrected initially, the model uses its own previous British spellings as an established convention, claiming it is simply following the context's rules rather than admitting a dialect drift.

Original post →

More from Models

Models channel →