Swahili is pretty phonetic, if you can read IPA it's [ta.fa.'ða.li] If you can't, its basically tah-fah-th(th in this)-a-lee (i can't accurately do the sounds without having the IPA though, you can use http://www.yorku.ca/earmstro/ipa/ to help you with the ipa sounds you don't recognize.
Wow! Asante! Now I know I can officialy be polite when I ask for something in kiswahili!
If i remember right from my experience in Tanzani, isnt tafadhali more "please" in a command sense, rather than making your request polite ? I vaguely remember being corrected on that at dinner once