The link between linguistic deviation and translation techniques is enshrined in the conventionality of language use and communication. Linguistic deviation occurs when a text ignores conventional norms of a language in order to communicate a certain artistic merit and draw attention to the meaning of the message. The main objective of this paper is to interrogate how translation techniques used on bilingual billboard slogans in Cameroon lead to linguistic deviation and how such deviations affect communication and sociolinguistics. The corpus of this paper is composed of fifteen bilingual billboard slogans purposively selected from different parts of Cameroon. In terms of methodology, the data was collected by taking pictures of billboards and extracting their slogans. A qualitative descriptive method of document analysis was used with the help of Leech’s linguistic deviation theory and Jakobson’s communication functions. Regarding the results, the study identified graphological, semantical, grammatical and lexical deviations on the selected billboards caused by translation techniques like literal, reduction, adaptation, borrowing, discursive creation, amplification and transposition. As a result of linguistic deviation, the messages that were finally conveyed through bilingual billboards looked absurd and sometimes nonsensical. The paper recommends that certified translators should be employed to translate billboard slogans from French to English.