This is peculiar. Might just be too early for the dust to have settled, but both tagesschau.de [1] and Le Monde [2] report both Spanish and English for to be spoken by the attackers.
Edit: The Guardian [3] also quotes only Spanish, but later speaks of an English-language announcement on a megaphone. Guess we'll have to wait for a bit until things converge to The Truth™ here.
[1]: https://www.tagesschau.de/ausland/amerika/haiti-praesident-m...
[2]: https://www.lemonde.fr/international/article/2021/07/07/hait...
[3]: https://www.theguardian.com/world/2021/jul/07/haiti-presiden...