Due to globalization and the spread in the use of foreign languages in the workplace, language needs have been regularly and increasingly researched, whether from linguistic, psychological or socio-economic perspectives. The use of these languages, far from being neutral, gives rise to a whole set of attitudes, feelings, behaviours and representations from the speakers of these languages. It may also induce for employees situations of stress, work-related suffering and compromised promotion. This article deals with the interlinguistic insecurity of French employees using English as a foreign working language in oral communication. A quantitative research enquiry involving 642 French employees from various fields of activity was carried out. It explored attitudes, feelings (for example foreign language anxiety or feelings of inferiority), behaviours (such as withdrawal) and representations (like awareness of shortcomings and desire for improvement) linked to interlinguistic insecurity in the workplace. The above attitudes and feelings were analysed in the light of three variables: gender, age and education level. The effects of these variables and their relevance were investigated. The results showed that education level was the prevalent variable and that interlinguistic insecurity is a real issue for higher and continuous education. Possible approaches to alleviate insecurity in the workplace were then considered on linguistic and cultural grounds.