The word of is commonly pronounced weakly, and the /f/ sound at the end of of is sometimes pronounced as . The expression “of course” was one that is considered a typical example. Is the /v/ in the word “of” often pronounced as before an unvoiced consonant.

I know I didn’t know this one coming when I was expecting it, but she was perfect. I am a native Thai girl. I know the words “of” in the phrase that I’m in college and the words “of course” have the same pitch. I learned the following rule: The word of is spoken with the sound “f”. From my reading of have in a number in English class, learn it as a rule had given me a (wrong) impression that it’s something important to be aware of. But, while looking for a material to back up this “rule,” I learned that this is merely a variation of the actual sound of the same phoneme /v/.