At the age of six, Obama and his mother had moved to Indonesia to join his stepfather. From age six to ten, he was registered in school as “Barry”[31] and attended local Indonesian-language schools: Sekolah Dasar Katolik Santo Fransiskus Asisi (St. Francis of Assisi Catholic Elementary School) for two years and Sekolah Dasar Negeri Menteng 01 (State Elementary School Menteng 01) for one and a half years, supplemented by English-language Calvert School homeschooling by his mother.[32][33] As a result of his four years in Jakarta, he was able to speak Indonesian fluently as a child.[34] During his time in Indonesia, Obama’s stepfather taught him to be resilient and gave him “a pretty hardheaded assessment of how the world works”.[35]
In 1971, Obama returned to Honolulu to live with his maternal grandparents, Madelyn and Stanley Dunham. He attended Punahou School—a private college preparatory school—with the aid of a scholarship from fifth grade until he graduated from high school in 1979.
I would bet that he only still knows a few words and phrases. You don’t usually retain fluency if you stop using a language at a young age.
I found this story googling.
https://www.quora.com/Could-Obama-speak-Indonesian I know Quora is not a primary source, but I’m just googling.
Bahasa is incredibly simple. It has no articles, genders, time conjugations or adverbs. You just say “I eat yesterday cake” for example
There are not even any plurals – if you really need to stress the plural form, then you just repeat the word again.
Confirmed with this speech he gave as President when in Indonesian.