Optimize Multilingual AI with High-Quality LLM Training Data
Appen empowers model builders to develop multilingual AI solutions that understand diverse linguistic, cultural, and contextual nuances. Enhance model accuracy, adaptability, and user experience across global markets with diverse, culturally relevant LLM training data.

Multilingual LLM Training Improves AI Performance
Multilingual AI enables LLMs to process and generate text across multiple languages, ensuring linguistic adaptability and contextual accuracy. These models leverage transformer architectures and self-attention mechanisms to capture syntactic and semantic relationships across languages.
Key Components of Multilingual LLM Training:
Tokenization
Essential for breaking text into processable units, especially in complex scripts like Chinese or Arabic.
Context Windows & Long-Form Understanding
LLM context windows fix context limits, impacting translation consistency and long-form coherence in multilingual tasks.
Cross-Lingual Transfer Learning
LLMs build shared representations across languages, allowing knowledge transfer between high- and low-resource languages.
Direct Translation Models
Some models, like Meta’s M2M-100, bypass English as an intermediary, improving efficiency for underrepresented language pairs.
Multilingual AI Training is Essential for Global Expansion
Multilingual AI is more than translation—it is about ensuring culturally relevant, and inclusive AI interactions. Localization ensures model output is context-aware, relevant, and inclusive, enhancing engagement and trust. This is crucial for global solutions, enabling accurate and accessible multilingual models.
Nuanced
Cross-lingual training helps AI systems grasp regional idioms, dialects, and linguistic variations, improving accuracy in sentiment analysis, question-answering, and content moderation.
Relevant
AI-powered translation models go beyond word-for-word translation, aligning model performance with cultural expectations, regulatory requirements, and user intent.
Global
Businesses expanding internationally require accurate, real-time multilingual AI to deliver globally relevant AI-driven solutions – powering global applications in search, customer service, and content generation.
Accelerate AI Translation & Localization
Want to scale your machine translation capabilities while ensuring linguistic and cultural accuracy? Learn how an expert-driven approach enhances your AI’s ability to engage global audiences.

Multilingual AI in Action
As the leading provider of multilingual LLM data, Appen supports top model builders and enterprises in refining their models for global applications.
Preference Ranking & Supervised Fine-Tuning for 70+ Dialects
Appen supported a global technology company in improving its LLM’s performance across more than 70+ dialects and 30+ languages by providing structured human feedback. Contributors engaged in multi-turn dialogues, ranking responses from five model variations based on coherence, factuality, fluency, and instruction-following. 250,000+ dialogue rows were collected, refining model outputs for supervised fine-tuning. The project expanded from 10+ dialects in 5+ languages to 70+ dialects, enhancing cultural alignment and language accuracy in model responses.

How Microsoft and Appen Innovated AI Translation for 100+ Languages
Microsoft Translator partnered with Appen to make synchronous multi-language communication possible across 110 languages – including rare and endangered dialects like Maori and Basque.
How a Design Software Enhanced AI Image Generation in 20+ Languages
A leading graphic design software company partnered with Appen to refine a multimodal AI model that generates original images from text prompts in 20+ languages—ensuring quality and relevance across diverse regions.
How Appen Can Help
With 25+ years of linguistic expertise, Appen delivers tailored multilingual AI data solutions, ensuring your AI achieves high accuracy, fluency, and cultural alignment.
Translation
Translate data to your target languages – building multimodal AI datasets across speech, text, image, video, and more.
Localization
AI data collection & annotation from experts in your target audience, ensuring linguistically and culturally relevant results.
Evaluation
Train natural fluency in your models with human-in-the-loop model evaluation and red teaming to align your AI with end users across the globe.
Fine-Tuning
Fine-tune your model's performance with post-editing to correct grammatical, spelling, and stylistic errors to achieve high-quality end-user results.
Why Choose Appen?
Founded in 1996 by linguist Dr. Julie Vonwiller, Appen specializes in high-quality, culturally accurate language data, powered by our AI Data Platform which combines machine translation with human oversight.
Global Reach
Appen’s 1M+ global workforce ensures scalability across diverse languages, including low-resource ones.
Proven Quality
Decades of expertise guarantee accurate, culturally relevant translations tailored to client needs.
Advanced Tools
Industry-leading technology combines MT and human oversight for optimal results.
Custom Solutions
Flexible workflows align with unique client objectives for seamless project execution.
Trusted Expertise
Experienced in rare languages, ensuring cultural and linguistic precision. Success with top tech, retail, and government customers demonstrates consistent results.
Improve Multilingual LLM Performance Today
Expand your AI’s global reach with Appen’s multilingual LLM training and localization solutions. With 25+ years of expertise, a diverse global workforce, and innovative tools, we help you build culturally relevant, high-performing models. From translation and localization to evaluation and post-editing, we provide the talent, precision, and scalability needed to ensure seamless AI experiences across languages and cultures.