The speaker talked about the Fusion programming language, which aims to reduce the number of features in programming languages by using a single concept called a Fusion feature. They discussed the use of algebraic effects to model non-functional effects like state changes and IO operations. Types are also used as first-class features in Fusion, allowing for easy constraint of type parameters and the handling of mutable references. The speaker emphasized the importance of static analysis of effects used in code, as library code can have unexpected effects. The talk also mentioned that the Fusion language is still under development and has two backends: an interpreter running on the JVM and a C backend using the beam devisor garbage collector.