Yes. Natives don't say every word clearly. They only say the important words clearly. In *come to the store*, the important words are *COME* and *STORE*. The middle words *to the* are not important, so they make them very small and fast. *to the* = *tuh-thuh* -> sounds like *"muh"* when fast. So: Slow: come TO THE store Fast: come *tuh-thuh* store = *kum muh store* It's normal. All natives do it.