GraalVM is a project based in Oracle Labs developing a new JIT Compiler and Polyglot Runtime for the JVM. Further details can be found on the OTN site.
Graal SDK is the Graal Standard Development Kit that contains long term supported APIs.
Graal is a dynamic compiler written in Java that integrates with the HotSpot JVM.
Truffle is a framework for implementing languages and instrumentations that use Graal as a dynamic compiler.
Tools contains a set of tools for Truffle guest langauges implemeted using the instrumentation framework.
Substrate VM is a framework that allows ahead-of-time (AOT) compilation of Java applications under closed-world assumption into executable images or shared objects.
Truffle and its dependency Graal SDK are licensed under the GPL 2 with Classpath exception.
The Graal compiler is licensed under the GPL 2.
The Substrate VM is licensed under the GPL 2.