Ackowledgments

We would like to thank University of Pennsylvania Libraries for providing an Open Educational Resources (OER) platform to publish this textbook series. We would also like to thank the Center for East Asian Studies, Penn Language Center, and James Joo-Jin Kim Center for Korean Studies for their sponsorship and support in the form of various grants. Thanks to their support and belief in our vision, we were able to successfully publish this complete second edition of the YSK series in the form of OER.

We also thank Yune Kim for her creative artwork and cover design; Jen Ramos, Dongin Kim, and Tracy Zhang for editing and creating the OER website; Hyunjun Ahn and Ejun Hong for their voice talent work; and Charlotte Fox for the book design. Their invaluable assistance has been instrumental in the fruition of the YSK project. We are grateful to Pixabay and OER Commons for access to their clip art and pictures. Any errors remaining in the current edition are our own.

Last but not least, we would like to express our heartfelt gratitude to our colleagues and students who have accompanied us on the journey of Korean language teaching. Their contributions and support have played a crucial role in shaping and updating the content of the second edition of the YSK series.