It is undeniable that English has become the most popular foreign language in Vietnam nowadays. Nevertheless, among the millions of people speaking English in Vietnam, there are many people who make mistakes in pronunciation. This creates some typical features of so-called “Vietnamese English”. This paper focuses on the mistakes made by Vietnamese users of English when pronouncing the four English sounds /∫/, / /, / / and / /. Reasons for the mistakes and some tentative suggestions to mitigate the problem are then discussed. The mistakes are identified in terms of both wrong manner of articulation and wrong.