For those of your tutors who are helping Hebrew speakers to understand the intricacies of English spelling and pronunciation, I would offer the following observation about what I call the magic letter "H".
In Hebrew, the softer pronunciation of certain letters is changed to a harder form by the introduction of the "dagesh" which is a dot placed in the middle of the relevant letter. A particular example is פ Fay that becomes a פּ Pay when the dagesh is introduced. In English, the letter H is the equivalent of the dagesh, although in reverse, as it softens the hard consonant that precedes it or changes the form of pronunciation. So the letter P is pronounced as an F when it is followed by an H, thus PH = F in Philosophy (twice!).
The letter G will also become an F in 'rough', 'cough,' and 'tough'. The G will become silent in 'bough' and 'plough'. An S will be changed to a sibilant Sha when followed by an H. The C becomes Che in 'chat' and 'chess'. The T also changes. There are, of course, exceptions so students need to watch out for the particular effect of the letter H that is both a consonant and an aspirant and is also an alchemist (ironically a word where the alchemy does not work!).
Yoel Sheridan is the author of "From Here to Obscurity" and "Gold Ducats and Devilry Afoot".