Many children with developmental language disorder (DLD) exhibit difficulties with phonology, i.e. the sounds of language. Children with any degree of hearing impairment (HI) are at an increased risk of problems with spoken language, including phonology. The cause of these difficulties is unknown in children with DLD, and is often assumed to result from reduced hearing acuity in children with HI. Variability in terms of language outcomes is large in both groups, and determining if a child's language ability is within normal limits or not is problematic. A task that has proven useful in differentiating typical from atypical language development is nonword repetition, in which the child listens to a word form without meaning and repeats it back immediately. Performance in nonword repetition tasks is a potential indicator of language ability in both children with DLD and children with HI. However, it has not been established exactly what the task measures. 9 ACKNOWLEDGEMENTS First and foremost, I would like to thank Christina Samuelsson, my main supervisor. Thank you for supporting me and showing unwavering interest in my work throughout this project, and for encouraging me to do research in the first place. Always keeping standards high, you have been generous in sharing your knowledge and creativity, and in helping me correct the mistakes you have given me the freedom to make. Next, I thank my co-supervisor, Björn Lyxell. It has been a true privilege working with you, and my only regret is that I did not bother you with more questions. With calm enthusiasm, you have inspired me to look at the bigger picture, and to never lose touch with the human behind the data. My many thanks to Ulrika Löfkvist. You have been my guide to everyday reality for children with hearing impairment and the speech-language pathologists working with them. Your theoretical and practical resourcefulness has really been invaluable to me, and to this project. My PhD work has been completely reliant on collaboration with hospital clinics and preschools. I would like to thank everyone that have taken their time to help me, with special mention of