This book explores the development of C-tests for providing efficient measures of foreign language proficiency in eight different languages: Arabic, Bangla, Japanese, Korean, Turkish, French, Portuguese, and Spanish. Researchers report on how C-test principles were applied in creating the new language tests, with careful attention to language-specific challenges and solutions. The final, five-text C-tests in all languages demonstrated impressive psychometric qualities as well as strong relationships with criterion variables such as learner self-assessments and instructional levels. These test development projects provide new tests for use by foreign language researchers, and they demonstrate innovative and rigorous test development practices in diverse languages.