Augmentative and alternative communication (AAC) users are highly diverse as their communication needs depend on many factors, such as motor ability, cognition, age, education level, and overall preferences. This chapter introduces the concept of tinkerability for AAC. We conjecture that Tinkerable AAC (TAAC) has the potential to empower AAC users, developers, and researchers to fine-tune, adapt, and explore better communication solutions in tandem with the system. We present a framework for tinkerable AAC that concretely links its qual-ities to AAC research and development areas and subareas. To demonstrate the viability of tinkerable AAC, we present a tinkerable predictive text entry system for it. It allows users to adjust many aspects of the system during use, ranging from the text prediction algorithms in the back end to the parameters underpinning the keyboard layout in the front end. In addition, it also allows AAC system devel-opers to adopt state-of-the-art language models and enables AAC researchers to carry out in-situ research experiments. We discuss the design space opened up by tinkerable AAC and its potential in empowering the AAC community to co-design individually tailored solutions for users.