Consider the difference in pronunciation of “have:”
1. I have a dog.
2. I have to go to the store.
In the first case, the ending consonant is generally pronounced as “v,” just as the word is written. But in the second case, it is generally pronounced as “f,” as in “I haff to go to the store.” I don’t know why that is, and I wasn’t aware of it until I read a post on it.
That’s interesting, at least to me. I tend to be interested in quirks of the English language, of which there are many.