Senior AI Engineer (Voice Systems)

About this role

Senior AI Exprt - Voice Bot Systems · Work Location: o Hanoi: TechnoPark Tower, Vinhomes Ocean Park, Hanoi o Hochiminh: Vincom Dong Khoi, HCM Job overview We are looking for an AI Expert to join our team as the technical anchor for next-generation real-time voice bot systems. While our Software Engineers focus on integration and infrastructure, this role owns the intelligence layer — designing, training, evaluating, and optimizing the AI models that make voice interactions actually work: from acoustic understanding to natural speech synthesis, speaker identification, and language comprehension in noisy, real-world conditions.

The ideal candidate has built voice AI systems in production — not just integrated APIs, but understood what's happening inside them and made deliberate choices about model architecture, training data, evaluation methodology, and latency trade-offs. You will work directly with Software Engineers to move models from research into production and with product stakeholders to define what "good" means for a voice bot. Key Responsibilities: Voice AI Research & Development Design and develop end-to-end voice pipelines: ASR → NLU → dialogue management → TTS, with full understanding of the trade-offs at each stage Research, evaluate, and fine-tune models for Vietnamese-language voice tasks: ASR accuracy on domain-specific vocabulary (vehicle names, locations, plate numbers), TTS naturalness, speaker diarization in multi-party calls Build and maintain evaluation frameworks for voice AI quality: Word Error Rate (WER), Real-Time Factor (RTF), MOS scoring, speaker turn accuracy, end-to-end latency benchmarks Model Fine-tuning & Training Fine-tune ASR models (Whisper, Gipformer, wav2vec 2.0) on domain-specific and accent-specific Vietnamese data Fine-tune TTS models (F5-TTS, VoxCPM2, VITS) to produce natural, brand-consistent voice output for CSKH scenarios Build and curate training datasets: audio collection pipelines, annotation tooling, data quality validation Apply speaker diarization and voice activity detection (VAD) to segment and attribute multi-speaker call audio LLM & NLU Integration Design prompt strategies and context management for LLM-driven dialogue in voice-specific constraints (no markdown, short sentences, natural prosody cues) Develop intent classification, entity extraction, and slot-filling components tuned for spoken Vietnamese, including noisy transcripts from imperfect ASR Evaluate and mitigate hallucination in voice LLM pipelines, including ASR-grounded prompting and transcript correction techniques Production & Optimization Optimize inference latency for real-time constraints: quantization, batching, streaming inference, model distillation Design and run A/B experiments on model variants in production; define statistical evaluation criteria for voice quality metrics Collaborate with Software Engineers on model serving architecture (GPU inference servers, ONNX runtime, TorchServe, Triton) Build monitoring pipelines for model performance drift, ASR degradation, and TTS quality regression in production Qualifications: Education Bachelor's or Master's degree in Computer Science, Electrical Engineering, Applied Mathematics, Linguistics, or a directly related field.