Sign languages are the means of communication of deaf community around the world. They are fully developed linguistic systems that have their own grammar, rules and linguistic structure. This thesis explores the complexity of their structure, along with historical changes and some of the many distinctions between different sign languages. The main aim is to provide a deeper understanding of how sign languages create new and more complex meanings through morphological processes, but also to highlight the unique characteristics that distinguish them from spoken languages. American Sign Language (ASL) is the language in focus, as the most research has been carried out on it. A significant section of this paper is devoted to the process of compounding, which is the most productive morphological process in sign languages, with particular attention paid to the Al-Sayyid Bedouin Sign Language (ABSL). Since this language is only 75 years old, it provides a noteworthy insight into the emergence of new compounds, but also into the evolving nature of sign languages in general.