I will now show a few more photos - see if you can figure out with the extra info at hand.
Here are my comments on your attempts, which are very much appreciated:
Melissa, you are right, they are not quite berries yet, but will soon be. Compostpyle, they are neither goji berry nor wolf berry - we don't have them around here.
Jenny, I'm surprised you haven't seen these, but can't blame you, you are a writer, not a farmer...! Lee, they do look like langsat don't they, except langsat grow closer to the trunk (shorter stalks), shown below:
|These are 'Langsat', really sweet and tasty fruit|
Chai Chai, Nancy, they are not Acai berries even though we have a type of palm tree that produces fruits similar in shape to them. These berries are not from palm trees.
Thanks also to Clarissa, Laura and Rayna, whose comments I had responded to individually earlier.
Faith, I was about to post this when your comment came in! You made me laugh over googling images for tropical fruit trees to find the answer! And you had analyzed well too - as to why they are not eggplant or longan...
Here are some more clues:
|This is how they looked like two weeks before|
|As you can see they sprout out from branches|
and trunks of a tree, not a palm tree
|Could they be Grapes?|
|These are at slightly more advanced|
Would you care to try again?