Effective communication requires social and cultural norms in addition to linguistic competence. This study explores the challenges that people who studied English in Burundi face when communicating in English. It, also, seeks to determine the causes of these challenges. To this end, people who often participate in meetings, conferences, or workshops where the working language is English were identified and given a questionnaire made of open-ended and multiple-choice questions. Results indicate that respondents do not know which elements of the language are essential for communication. They consider that the linguistic competence alone is enough for being able to communicate. For example, learners consider that being able to pronounce correctly the language and knowing the technical terms may be enough for them to communicate their ideas. It is also found out that the causes of this lack of effective communication may lie in the inadequate teaching methods adopted in Burundi.