Acknowledgements

Thanks to my advisor and mentor Jan Edwards for recognizing my potential, plucking me from the Masters program, and giving me the opportunity to be a part of her lab. Jan changed my life by giving me a purpose and place to develop my skills.

Working in the Learning To Talk lab was an enriching experience. I had the freedom to explore and experiment, to fail and learn. I entered as a speech pathologist and left a data scientist. Thanks to Ben Munson, Mary Beckman, Franzo Law II, Matt Winn, Pat Reidy, Tatiana Thonesavanh, Alissa Schneeberg, Kayla Kristensen, Allie Johnson, Michelle Erskine, and Lizzy Hill. Special thanks to Nancy and Bob Wermuth for being role models.

A lot of smart and busy people gave me their time and thoughts. Thanks to the faculty who were always willing to advise me: Margarita Kaushanskaya, Audra Sterling, Jenny Saffran, Courtney Seidel, Katie Hustad. Thanks for Susan Ellis Weismer for taking me under her wing and helping me through some stressful periods. Thanks to Bob McMurray for giving an enthusiastic, eye-opening lecture at ASHA 2013 about how eyetracking data works as a measure of word recognition. Thanks to Tim Rogers for being on my prelim committee.

Thanks to my compatriots at Waisman and elsewhere whom I commiserated with often: Pierce Edmiston, Courtney Venker, Ron Pomper, Martin Zettersten, Liz Premo, Janine Mathee, Phoebe Natzke, whoever happened to be around in Rita's lab on a given day. Thanks to Lolo for telling me that graduate training for speech pathology is a career for a linguist.

This research would not have been possible without the families and children who participated in our research.

I am grateful for the financial support from the NIH grants that supported me as a trainee or as a research assistant: NICHD Grant 2-T32-HD049899 to Maryellen MacDonald, NIDCD R01 DC012513 to Susan Ellis Weismer, Jan Edwards, and Jenny R. Saffran, and NIDCD T32 DC05359-10 to Susan Ellis Weismer. The data for this project were collected as part of the Learning to Talk project which was funded by NIDCD R01 DC002932 to Jan Edwards, Mary E. Beckman, and Benjamin Munson. Thanks to departmental administrators who kept the machine running: Maureen Garity, Amanda Talbert, Choutae Yang.

I spend all day working in R and RStudio. I want to thank Hadley Wickham for fixing the language and for working in open source so that I could learn from his work. Thanks to other RStudio people: Yihui Xie, Kevin Ushey, Jenny Bryan, and Mara Averick.

I've spent the last two years basically teaching myself Bayesian statistics. Thanks to the Jonah Gabry, Paul-Christian Bürkner and the Stan team for a great ecosystem; David Kaplan for talking me through some of my early doubts; and Richard McElreath for putting his Statistical Rethinking course on YouTube.

Recognition is due for the community of statisticians, data scientists, psychologists, and language scientists whom I spent idle moments with on Twitter. There are too many of you to name. Thanks to the fellow graduate students, post-docs and others early in their research careers for helping me feel a sense of community. I often used the medium as a way to think out loud as I worked through modeling, programming or plotting problems. Thanks to those who chimed in to answer questions, suggest references, or offer feedback.

I will finish by thanking the people closest to me. I grew up on dairy farm in rural Wisconsin and I was the seventh of ten children. That explains about 70% of who I am and whom I've become. My mom is nothing short of a superhero. My dad has been a paragon of steadiness and selflessness. Thanks to my siblings and their families for keeping me from taking myself too seriously. Thanks also to my-laws for being close to us.

Finally, thanks to my wife Amanda. None of this would have been possible without your love, support, humor, and nerdery. People sometimes thought I was a workaholic because I would get to my office at 8 am. But really, I just wanted to ride the bus with you in the morning. We started a family together! Shout out to Kiki and Nooper for the snuggles.