Vietnam, Malaysia, Laos, Cambodia – which of these countries does not speak French as an official language

Of the countries you listed, Malaysia does not have French as an official language. The official language of Malaysia is Malay. In contrast, Vietnam, Laos, and Cambodia all have historical links to France and recognize French in various capacities, often as a secondary language, but it's not considered an official language in these countries. However, Cambodia recognizes French in certain contexts, mainly due to its colonial history.