AI Language Engineer

Cresta is on a mission to turn every customer conversation into a competitive advantage by unlocking the true potential of the contact center. Our platform combines the best of AI and human intelligence to help contact centers discover customer insights and behavioral best practices, automate conversations and inefficient processes, and empower every team member to work smarter and faster. Born from the prestigious Stanford AI lab, Cresta's co-founder and chairman is Sebastian Thrun, the genius behind Google X, Waymo, Udacity, and more. Our leadership also includes CEO, Ping Wu, the co-founder of Google Contact Center AI and Vertex AI platform, and co-founder, Tim Shi, an early member of Open AI. Join us on this thrilling journey to revolutionize the workforce with AI. The future of work is here, and it's at Cresta. About the Role We are seeking a versatile AI Language Engineer to design, build, and enhance natural language systems that power intelligent products and experiences, spanning both text and speech domains. This role combines linguistic insight, applied NLP expertise, and AI engineering execution to advance language understanding, generation, and evaluation across real-world applications. The AI Language Engineer will collaborate with product and engineering teams to translate language challenges into scalable AI solutions. You must be located in the United Kingdom. Key Responsibilities AI Language Engineering & Model Work Design, develop, and refine large language model (LLM) workflows, including context engineering, prompt design, and evaluation frameworks to steer and improve model behaviors. Build language processing components for features such as intent detection, entity recognition, summarization, retrieval-augmented generation (RAG), and conversational response quality. Develop speech-to-text (ASR) and text-to-speech (TTS) workflows and evaluation frameworks, bridging audio-feature/signal-level processing with LLM-driven reasoning and orchestration. Fine-tune and evaluate models using quantitative and qualitative metrics to ensure robust performance across tasks. Applied NLP & Linguistic Analysis Analyze model outputs and conversational data to identify patterns, gaps, and failure modes, translating findings into actionable improvements. Define and apply linguistic evaluation criteria to ensure tone, clarity, intent understanding, and contextual accuracy. Experiment with prompt structures, retrieval strategies, and linguistic patterns to improve accuracy and robustness. Data & Experimentation Drive R&D-style exploration on cutting-edge speech and language systems where best practices are still emerging, rapidly prototyping novel approaches and validating them through rigorous experimentation. Lead data preprocessing, annotation, and language dataset creation, building reliable training and evaluation corpora. Design experiments to test model adaptations and new techniques, tracking performance and iterating based on data insights. Engineering & Product Integration Collaborate with software developers to integrate language models into production systems and ensure scalable deployment. Build tooling for model evaluation, monitoring, and continuous improvement pipelines. Extend evaluation and monitoring tooling to support large-scale, automated speech quality measurement for TTS and ASR in offline tests and production. Support performance optimization, model serving architecture, and infrastructure integration. Cross-Functional Collaboration Partner with product managers, conversation designers, UX researchers, and stakeholders to connect language capabilities with business objectives. Serve as the NLP & language subject-matter expert within multidisciplinary teams. Documentation & Knowledge Sharing Document methodologies, evaluation findings, best practices, and language guidelines to promote shared knowledge and reproducible workflows. Present results and recommendations clearly to internal and external stakeholders. Required Qualifications Bachelor’s or Master’s degree in Computer Science, Computational Linguistics, AI, Machine Learning, Linguistics, Cognitive Science, or a related field. Demonstrated experience applying NLP concepts and techniques (classification, entity extraction, semantic analysis, summarization, prompting, RAG). Strong programming skills in Python with familiarity in NLP/AI frameworks (e.g., Hugging Face Transformers, TensorFlow, PyTorch). Experience with data preprocessing, model evaluation, and language dataset design. Excellent analytical skills and ability to diagnose and communicate model behavior, linguistic patterns, and performance trade-offs. Strong collaboration and communication skills across technical and non-technical stakeholders. Preferred Skills Doctor’s degree in Computer Science, Computational Linguistics, AI, Machine Learning, Linguistics, Cognitive Science, or a related field. Familiarity with multilingual NLP challenges and cross-locale language modeling. Background in linguistic analysis, discourse, or semantics. Experience with speech processing (ASR/TTS), including audio feature pipelines or research in phonetics. Experience with production deployments, ML ops, and scalable systems in cloud environments (AWS, GCP, Azure). We have noticed a rise in recruiting impersonations across the industry, where scammers attempt to access candidates' personal and financial information through fake interviews and offers. All Cresta recruiting email communications will always come from the @cresta.ai domain. Any outreach claiming to be from Cresta via other sources should be ignored. If you are uncertain whether you have been contacted by an official Cresta employee, reach out to recruiting@cresta.ai