"2,200 in Burundi (2004). L2 users: 390,000 in Burundi (Francophonie 2007)" What is your source for the first number (2004) and is that mother tongue ? In the 2008 census they only provide languages literacy rates, which is not "mother tongue". For the second number, the 2008 census says 665,189 literates in French, among them only 17,724 have French-only literacy (which could be the nearest criteria for mother tongue, but it could also be French-speaking African immigrants which have learned to write French but not as their mother tongue). Here is an overall picture of the languages in Burundi (my work based on census data) : (in French) : https://fr.wikipedia.org/wiki/Langues_au_Burundi. Best regards, Loup Solitaire
We will update the L2 speaker population for French [fra] in Burundi in the 19th edition.