They do speak French in Madagascar, however, it is not their primary language. The national language of Madagascar is Malagasy. Malagasy is the Austronesian language spoken in various forms by the majority of the population. French and English are also spoken.
a good proportion of Malagasies speak French, because French was the colonial ruler between the 1890s and 1960. French is spoken less frequently by uneducated people and the younger generations.
Chat with our AI personalities
As in a lot of these cases, the area was under the control and/or colonized by another more powerful country. In this case when monarchy collapsed in 1897, the island was absorbed into the French colonial empire, from which the island gained independence in 1960. Many countries in South America speak Spanish or a form of it for the same reason.