The other day I heard a Nigerian refer to upholstery as 'ufolstery.' I had to think for a minute to figure out how he got that pronunciation. Actually, I think there are two possibilities.
In some tribal languages, they do not make the 'p' sound. One of these tribal groups tends to sell a lot of fabric in the market. When I'm looking for purple fabric, I now pronounce it 'furful' in order to be understood.
The other possibility is that from a phonetic perspective, when you see a 'ph' in a word, it should be pronounced as an 'f' sound as in 'phone.' Interesting. I never consciously noticed before that there is a 'ph' in upholstery.