The article deals with the innovative, cutting age solution within the language testing realm, namely computer adaptive language testing (CALT) in accordance with the NATO Standardization Agreement 6001 (NATO STANAG 6001) requirements for further implementation in foreign language training of personnel of the Armed Forces of Ukraine (AF of Ukraine) in order to increase the quality of foreign language testing. The research provides the CALT method developed according to NATO STANAG 6001 requirements and the CALT algorithm that contains three blocks: "Starting point", "Item selection algorithm", "Scoring algorithm" and "Termination criterion". The CALT algorithm has an adaptive ability, changing a complexity level, sequence and the number of items according to the answers of a test taker. The comparative analysis of the results of the CALT method piloting and the paper-and-pencil testing (PPT) in reading and listening according to the NATO STANAG 6001 requirements justifies the effectiveness of the three-level CALT method. It allows us to determine the following important benefits of CALT: test length reduction, control of measurement accuracy, objective assessment, improved test security, generation of a unique set of items, adaptive ability of the CALT algorithm, high motivation of the test takers, immediate score reporting and test results management. CALT is a qualitative and effective tool to determine test takers' foreign language proficiency level in accordance with NATO STANAG 6001 requirements within the NATO Defence Educational Enhancement Programme. CALT acquires a special value and relevance in the context of the global COVID-19 pandemic.