* The specific device and its software version: Different manufacturers and models have different voice packs and functionalities. Some may have more detailed instructions, warnings, or points of interest information than others.
* The route complexity: A longer, more complicated route will necessitate more instructions and warnings.
* The occurrence of unforeseen events: Traffic jams, road closures, and other unexpected events will trigger additional announcements.
Therefore, there's no single answer to how many things a sat nav can say. It's a vast and variable number ranging from dozens to potentially thousands of different phrases and sentences in a single journey, depending on all the factors above.