The talk is about using the Guile programming language and the Zig systems programming language together. The speaker demonstrates how to create a library in Zig and call it from Guile using the Zig compiler and Guile libraries. They also show how to create and manipulate arrays using both languages together. The speaker emphasizes the benefits of using a combination of languages rather than relying on one language to do everything. There is a brief Q&A session at the end.