In the present day Mandarin Chinese has become a commonly taught language in the U.S. Mandarin is widely taught in colleges and universities; K-12 Chinese programs, including immersion programs, have also grown rapidly. However, to date little research has been conducted on the latter programs. This study examines immersion programs in elementary schools. I investigate three aspects: 1) teaching methods in Chinese immersion programs, 2) acquisition of grammatical patterns, and 3) computer assisted methods for character learning. I adopted a qualitative approach; the methods I employ include observation, interviews, questionnaires, and tests. Data were collected from two immersion programs and two non-immersion programs in a Southwestern city in the U.S. The first study compares the teaching methods used in Chinese immersion and non-immersion programs. It is found that the two immersion programs adopted the functional approach with explicating in each class time, while the non-immersion programs used the analytical approach with practicing in context in most classes. The immersion students produced spontaneous speech in each class, while non-immersion language class students did not. The second study examines how immersion learners acquire the "ba"-construction and time phrases. We found that immersion students produced not many "ba" sentences but a large number of time phrases. However, in terms of accuracy, "ba" sentences were produced almost flawlessly, while time phrases were often placed incorrectly in a sentence. This result is quite different from what we find in adult learners who mostly acquire Chinese in a non-immersion setting. It shows that immersion learners' acquisition differs from both L1 acquisition and L2 acquisition by adults. The third study investigates how computer-assisted methods help students learn Chinese characters. I compare immersion learners with heritage learners with respect to how they respond to computer-assisted methods. No difference is found between the two groups of learners in terms of their performance in character recognition, pronunciation and writing. It is also found that while computer assisted materials helped with character recognition, it did not help with character writing. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]