"People speak French in Cameroon."
Translation:Les gens parlent le français au Cameroun.
When you speak about a country, you will use "au" if this country is Masculin and "en" if it is féminin or if it starts with a vowel or a H :
And how do you know if the country is Masculin or Feminin? .... I have bad news, there is no rule, you have to learn it :/
Should this also accept "Des gens..."? "Les gens" would seem to mean "All the people", which is not true (though that doesn't matter in the sense of whether a sentence can be used by Duo). Would "Des gens" translate to "People" as in "(Some) people"?