When people interact with AI chatbots, they often assume that changing the language of a prompt simply changes the language of the response. However, new research from Anthropic suggests that the language you choose may also influence how the AI responds—not just what language it speaks.
According to the company’s latest study, Claude AI displays noticeable differences in tone, warmth, and reasoning depending on the language used in a conversation.
Anthropic Analyzed More Than 309,000 Claude Conversations
To better understand Claude’s behavior, Anthropic examined approximately 309,000 anonymous conversations across its latest AI models, including Claude Sonnet 4.6, Claude Opus 4.6, and Claude Opus 4.7.
The research focused on interactions conducted in the 20 most commonly used languages on the platform. Rather than evaluating factual accuracy, the study analyzed conversations involving advice, opinions, and feedback—situations where responses are often subjective and can vary in style.
The goal was to understand Claude’s behavioral patterns across different languages instead of measuring whether its answers were correct.
Hindi and Arabic Produce Warmer Responses
One of the study’s most striking findings was that Claude tends to provide significantly warmer responses when users communicate in Hindi or Arabic.
In these languages, Claude was more likely to:
- Use polite and encouraging language.
- Express appreciation for users’ ideas.
- Include light humor when appropriate.
- Offer reassurance without being explicitly asked.
- Adapt its tone to motivate users and encourage further exploration.
For users communicating in Hindi, the AI often appeared friendlier and more supportive than when answering identical questions in English.
English Responses Are More Analytical
The experience changes considerably when interacting with Claude in English.
According to Anthropic, English conversations generally feel:
- More formal.
- More evidence-based.
- More analytical.
- More willing to challenge assumptions.
- More likely to point out mistakes proactively.
Instead of simply agreeing with users, Claude often questions reasoning and provides detailed explanations backed by logic and evidence.
The company identified this contrast as the largest behavioral variation across all tested languages.
Four Behavioral Dimensions
To compare responses consistently, Anthropic categorized Claude’s behavior into four major dimensions:
- Deference vs. Caution
- Warmth vs. Rigor
- Depth vs. Brevity
- Candor vs. Execution
These categories allowed researchers to evaluate Claude’s communication style independently from the factual correctness of its answers.
Among these dimensions, Warmth vs. Rigor showed the greatest variation across languages.
Anthropic explained that Claude leaned most toward warmth in Arabic and Hindi, while conversations in English and Russian emphasized analytical rigor and critical thinking.
Different Claude Models Have Different Personalities
The study also found that Claude’s communication style changes depending on which model is being used.
Claude Sonnet 4.6
Claude Sonnet 4.6 emerged as the warmest model in the research. It frequently:
- Used humor naturally.
- Matched the user’s conversational tone.
- Offered encouragement and reassurance.
- Maintained a friendly, approachable style.
Claude Opus 4.7
Claude Opus 4.7 displayed a much more analytical personality.
It tended to:
- Challenge assumptions.
- Highlight potential risks.
- Apply deeper reasoning.
- Acknowledge its own limitations.
- Encourage critical thinking rather than agreement.
Claude Opus 4.6
Claude Opus 4.6 occupied a middle ground.
Researchers found that it generally:
- Stayed focused on the user’s original intent.
- Delivered concise responses.
- Avoided unnecessary elaboration.
- Prioritized direct execution over extended discussion.
Why Does Language Change AI Behavior?
Anthropic emphasizes that these differences do not mean Claude holds different beliefs depending on the language being used.
Instead, the findings suggest that the AI has learned distinct communication styles from multilingual training data. Different languages often contain different cultural norms, writing styles, and conversational expectations, which may influence how the model frames its responses.
As a result, users asking essentially the same question in different languages may receive answers with noticeably different tones, levels of empathy, and reasoning styles.
Anthropic Wants More Consistent AI Systems
The company says it is continuing to investigate why these behavioral differences occur and how they can be better understood.
Anthropic believes that studying multilingual behavior will help improve future AI systems by making their responses more consistent while still respecting the natural communication styles associated with different languages.
As AI assistants become increasingly global, understanding how language shapes not only translation but also personality and reasoning may prove essential for building models that deliver reliable experiences to users around the world.