Here are some tongue-twisters to get used to the -ph and -f sounds.
A) Fifty thin professors photograph the Vatican.
B) Peter Piper picked a pitch for the fourth phase.
C) The trophy that Sophy won is fine so far.
D) A phenomenal pheasant flew through the photo-finish.
D) Phoebe had a phobia of phosphorescent phoenixes.
E) A physician doesn’t do physics; that’s a physicist.
F) Phone the Pope for a phrase of philosophy.