[Glossary](https://telxpress.com/glossary/) / AI # Large language model A **large language model** (LLM) is an AI system trained on vast amounts of text that can follow instructions and generate fluent language; it powers chat assistants and the conversation in AI voice agents. - AI - Updated October 11, 2026 - Written by the Telxpress advisory team 01 In depth ## What it is, why it matters and *what to ask a vendor* A large language model predicts likely text from the text it is given, which turns out to be enough to summarize a call, draft an email, classify a request or carry a conversation. The instruction you give it is called a prompt. On its own a model knows nothing about your business; it learns that from the prompt, from documents retrieved for it, or from being connected to your systems. For a growing business the model is rarely the decision; the vendor's use of it is. Two products on the same model behave differently depending on their prompts, guardrails, retrieval and integrations. The practical questions are about accuracy, confidentiality and what the system does when it is unsure. Ask which model a product uses and whether your data is used to train it, where the data is processed, how the vendor prevents hallucination (for example with retrieval-augmented generation), how often the model changes, and what tests they run after each change. Ask for a written data-handling statement. 02 Related terms ## Terms that usually come up *alongside it* - AI ### [Retrieval-augmented generation](https://telxpress.com/glossary/retrieval-augmented-generation/) Retrieval-augmented generation (RAG) is a technique in which an AI system first looks up relevant documents or records and then answers from them, so replies are grounded in your information rather than the model's memory. - AI ### [Hallucination](https://telxpress.com/glossary/hallucination/) A hallucination is a confident but false statement produced by an AI model, such as an invented policy, price or appointment slot, and it is the main accuracy risk in any customer-facing AI system. - AI ### [Agentic AI](https://telxpress.com/glossary/agentic-ai/) Agentic AI describes AI systems that can take actions to complete a goal, such as booking an appointment, updating a CRM record or sending a follow-up, rather than only answering questions. - Voice ### [AI voice agent](https://telxpress.com/glossary/ai-voice-agent/) An AI voice agent is software that answers phone calls in natural conversation, understands what the caller wants, answers questions, books appointments and transfers or takes messages when a person is needed. 03 At Telxpress ## Where this shows up *at Telxpress* The pages and articles where this term does real work: what we advise, build and support. - Page ### [AI Consulting & Strategy for Businesses](https://telxpress.com/ai-advisory/) Practical AI roadmaps, tool selection and deployment from advisors who also build it. Book a free AI readiness assessment. - Page ### [AI Agents & Business Automation](https://telxpress.com/solutions/ai/) AI voice, sales and support agents plus CRM and workflow automation, deployed and supported by our team. Based in Irvine, CA. - Page ### [Donya AI Voice Agent: Never Miss a Call](https://telxpress.com/solutions/ai/voice-agent/) Donya answers every call 24/7, qualifies leads and books appointments. Call the demo line to hear it. Built and run by Telxpress. Next step ## Want This Applied *to Your Business?* Book a free 30-minute AI readiness consultation. You'll leave with three AI opportunities specific to your business, whether you work with us or not. [Book My Free Consultation](https://telxpress.com/book/) [Take the Free AI Readiness Assessment](https://telxpress.com/ai-readiness/) [Or call 24/7: (949) 861-4500](tel:+19498614500) Last reviewed: October 11, 2026. Published by Telxpress, Irvine, CA.