PhD Dissertation
2015(c) 2015 AINARA IMAZ AGUIRRE ii Acknowledgments My deepest gratitude goes first to my supervisor, María del Pilar García Mayo, for her support, guidance, encouragement, and especially her confidence in my work from the very beginning. Despite her busy schedule, she always provided insightful comments and exhaustive feedback on drafts of the thesis, papers, conference abstracts, and even e-mail and WhatsApp communications. It was a pleasure to be your student. ¡¡Grazas por todo o que me ensinaches!! I am greatly thankful to the members of the committee and the two international experts Antonio Fábregas (University of Tromsø) and Roumyana Slabakova (University of Southampton), who gratefully accepted to read this work and whose comments, I am sure, will refine the quality of this work.