) Is this a single plant, or is it a group of plants (or stalks)? If single, quite possibly an ornamental. If multiple, most likely edible.
2) Have you ever seen any of the stalks (pseudostems) flower? Is it possible that it has flowered, but the fruit was small enough that you didn't think the ere actually bananas?
3) Is the foliage green or green with a good amount of red? If green, most likely edible. If it has a lot of red in the leaves and stems, and it is a single stalk it could well be an ornamental Abyssinian banana. They are quite popular in landscapes. The down side is that they will flower, and then die. They are propagated from seeds, not pups.
See
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