Claude's Personality Changes Across Languages

AGI Hunt · wechat · 2026-07-14

This article breaks down Anthropic's latest research, confirming that Claude models actually exhibit different "personalities" depending on the model and language used. Using personal experience as a starting point, the author notes that Sonnet feels warmer while Opus is more direct, with the research providing systematic evidence.

The research team analyzed roughly 309,815 anonymized conversations from Claude.ai, covering Sonnet 4.6, Opus 4.6, Opus 4.7, and 20 languages. They identified 3307 distinct values, clustered them into 339 categories, and ultimately distilled them into four main axes:

Key findings include:

Anthropic admits they still don't know why these differences emerge, though it might be tied to training data distribution, corpus composition, or cultural communication habits, nor are they certain if these differences are a good thing. The researchers plan to incorporate this value analysis into standard evaluations, trace it back to specific training data and phases, and determine if intervention is necessary.

Related event: Anthropic Maps How Claude's Values Shift Across Models and Languages(21 posts)→

Original post →

More from Research

Research channel →