What is a large language model (LLM)?
A large language model (LLM) is an AI model trained on very large amounts of text that can read, write, summarize and reason in everyday language. Google's machine learning course explains that LLMs work by predicting the next token, a word or piece of a word, and that the largest models contain hundreds of billions of parameters or more. Claude, GPT and Gemini are well-known examples.
Why it matters to a revenue leader
The LLM is the engine inside most AI sales tools, so its strengths and limits become yours. It is very good at language work: summarizing deal notes, drafting emails, pulling fields out of documents and answering questions about text it is given. It does not know your pipeline, customers or pricing unless a tool supplies that data, and it can state wrong things with confidence. When you evaluate any AI tool, ask which model it uses, what data it sees and how its answers get checked.
Example
A sales leader at an environmental services company pastes three months of notes from a stalled deal into an LLM and asks for a summary of the buyer's concerns. In seconds, the model groups the notes into budget timing, a competing bid and a missing site survey. It cannot tell whether the competing bid is still live, so the seller confirms that with the customer.
"For each AI tool we use, which model sits underneath it, and what data from our business does that model see?"