The research is focused on the aspect of functional speech adaptation of language interpreters who are gaining practical experience at the initial stage in the sphere of foreign-language military-professional communication and paying special attention to the search for original speech strategies to achieve the targets of the translation process in the most efficient way. The critical objective of the article is to theorize the functional speech adaptation and underscore the need and importance to develop interpreters’ unique creative strategies in the process of their adaptive professional maturation for the due carrying out of normal and special translation tasks under the conditions of operational military activities abroad. A detailed review of the scientific sources is carried out concerning research into definitions of linguistic terms such as: “adaptation,” “speech adaptation,” “speech strategies.” The author’s definition of the core of the term “Functional speech adaptation” is given and its main differences are outlined versus the definitions of the linguistic categories “adaptation” and “pragmatic adaptation” proposed by Russian linguistic theorists earlier. The most effective strategies for interpreting are reviewed, viz.: implementation of an interpreter’s anticipation, a strategy for target text forming from the ground of precision information, and a strategy for source text segmentation into minimal translation cells. The study applies the methods of definitional analysis, comparative analysis of theoretical principles with their generalization, theoretical synthesis of the concepts’ definitions, linguistic description method and linguistic modeling. The results of the conducted research make a significant contribution to studying functional speech adaptation of military interpreters in the implementation of interpreting and translation tasks on the foreign military sub-languages material. Moreover, the results of the study can be used for future research purposes of translation studies, theoretical and applied linguistics.