Many Large Language Models (LLMs) are primarily trained on a massive amount of English data. As a result, the Dutch output can sometimes sound unnatural, stiff, or contain outright translation errors (Anglicisms). Fortunately, you can significantly improve the quality of the Dutch output with the right system prompts, style instructions, and conscious guidance.

1. The Power of a Dutch System Prompt

The system prompt is the foundation of every interaction. By explicitly instructing the model to communicate in fluent, idiomatic Dutch, you prevent it from falling back on literal translations from English.

You are an experienced Dutch copywriter and editor. You always communicate in fluent, natural, and correct Dutch. You avoid literal translations from English (Anglicisms), use an active sentence structure, and apply the appropriate tone and register based on the context.

2. Setting Tone and Register

The Netherlands has specific social norms regarding politeness, directness, and professionalism. While Americans often opt for exuberant enthusiasm ('amazing', 'game-changer'), the Dutch business market prefers down-to-earthness and clarity.

Business formal: Use the formal 'u' form (optional in modern communication, but required for formal institutions), avoid buzzwords, and keep sentences compact.
Accessible / Informal: Use the informal 'je/jij' form, active verbs, and address the reader directly without becoming too informal.

3. Common Dutch Mistakes Made by Models

When you notice an AI struggling with Dutch, you often see the same patterns recurring:

Anglicisms in passive sentences: The model translates "It is recommended to..." literally as "Het is aanbevolen om...", whereas in correct Dutch "Wordt aanbevolen om..." or "Het verdient aanbeveling..." is more appropriate.
Unnatural word order: Adjectives or subordinate clause constructions that follow the English structure instead of Dutch verb-final or inversion rules.
Exaggerated superlatives: The use of overly strong praise that comes across as insincere in Dutch culture.

4. Practical Tips for Daily Use

Want to see immediate results in your prompts? Use the following rules of thumb:

Include negative constraints: Add to your prompt: "Do not use unnecessary jargon or English terms if good Dutch alternatives exist."
Let the model self-correct: For complex texts, specifically ask: "Check the text below for Anglicisms and rewrite it into natural, idiomatic Dutch."
Compare performance: Curious about how different open-source and closed models score on language proficiency? Check out our LLM Benchmark to see which model performs best with Dutch-language tasks.