Here's why:

* Citric Acid: Sprite contains citric acid, which gives it its tart flavor. Citric acid is a weak acid.

* Carbonation: The carbonation in Sprite is from dissolved carbon dioxide (CO2), which forms carbonic acid when dissolved in water. Carbonic acid is also a weak acid.

The combination of these acids makes Sprite slightly acidic. While the acidity is relatively low, it's still enough to contribute to tooth enamel erosion if consumed frequently.