Uzbek
It has been well said that once you have learned to speak Uyghur, you will be able to pick up Uzbek quite quickly. The hardest part will probably be treating Uzbek as an entirely separate language rather than just a variation on Uyghur. While to a large degree you may think of Uzbek as an “Uyghur with a different accent,” there are plenty of traps and “false friends” out there. So it is also important to learn the language from the inside and to understand Uzbek as a living product of a different language community.
Although in learning Uyghur I used grammars and various texts, right from the start, having acquired some Uyghur I became fairly functional in Uzbek without ever cracking open a textbook. However, I later found it necessary and helpful to undertake some more formal study of Uzbek.
Here are some of the resources I have picked up along the way.
ORTHOGRAPHY
Download a great pdf chart here.
Principal Orthographic Rules For The Uzbek Language
Uzbekistan government resolution on use of Latin based script translated by the Center for Academic Research.
ENTRY-LEVEL
Introduction to Uzbek Language
Source unkown
Uzbek Language Competencies for Peace Corps Volunteers
ERIC, via livelingua.com
Uzbek: An Elementary Textbook
Nigora Azimova
Available from Georgetown University Press.
FOR THE LINGUISTS
Uzbek Structural Grammar
(The Ural and Altaic Series Volume 18)
Andree F. Sjoberg
UZBEK IN OTHER LANGUAGES
Хитойча-Ўзбекча Сўзлашгич (Chinese-Uzbek Phrase Book)
Ilhom Qosimov & Li Rong
From Akademnashr
ISBN 978-9943-985-61-2