First of all, my gratitude goes to my supervisors, Pieter Muysken and Mily Crevels, who gave me the chance to explore this topic, and who have been my mentors during many years. I would like to thank Pieter for always being generous with his knowledge and ideas, for all his insights on the topics discussed in this dissertation, and for his unfailing positive-thinking and encouragement. Pieter’s role in my academic development started with the inspiring classes he taught, and I have been grateful ever since for the possibility to learn from him. Pieter, thank you for all the opportunities that you have given me! I would like to thank Mily for her huge contribution to my training, which also started long before this dissertation. Mily’s expertise and advice at every step were invaluable, and I am grateful for her dedication, support, friendship and trust, and for her guidance throughout the whole project. Mily’s incredible eye for detail, and her careful comments on many versions of each page of this work were crucial to avoid many pitfalls.