What is Natural language
Natural language is ordinary human language, like English or Spanish, as opposed to code.
In plain terms
Natural language means the words people normally speak and write, rather than a programming language. When a product lets someone type a plain sentence instead of clicking through menus or writing code, that is called a natural language interface. The name separates it from the strict, narrow syntax a programming language requires. A developer who works on natural language interfaces builds the part of a product that turns a plain sentence into something a computer can act on.
What it tells you about a developer
A developer who has shipped a natural language interface has worked on the seam between a model and the rest of a product. That is applied AI product work, and it pairs a model with ordinary application engineering.
Related
Read the lesson on Natural language More in What the tech words mean