letter and sound F in English

F is 4th consonant and it is articulated puffing out the air through the opening of lips. The combined  diagraphs  ph and gh also produces  (f) sound. F is never kept silent in words.

Example: Lough, Tough, Pamphlet, Physician etc

But in some words last gh sound is also missing

Example:  Bough, caught, Drought, Haughty Plough, Slight, Weight, Freight, Fright, Neighbour, Straight

>> GH sound is silent when GH comes after au, ou and I in words.

F letter is not found silent in English words as it is very forceful sound.

Common PH words with F sound

alphabet, dolphin, elephant, graph, orphan, phantom, phone, Pharma, pheasant,  Photo. Common GH words with F sound cough, enough, laugh, rough, tough. Some 4 syllables words starting with F sound February, forgiveness, fireplace, familiar, flabbergasted(ˈfla-bər-ˌga-stəd) firefighter, fascinating, finality, facetious, fabrication, fidelity, fenestration, feudalism, feminism,fermentation, firecracker, fashionista, fraternity, fascination, foreboding, fornication, federation, forestalling, fibrillation, finalizing, formality, futility, fantasizing, figuration, fertilizing, friendliness, foregoing, fabulousness, fatality, fabricated, foreclosure, fertilizer, forewarning, frivolity, forcefully, facultative, fascinated, foliation, femaleness, fastidious, forecasting, forgivable, fashionable, fathomable, ferocity, fulminating, formulation, financially, felicitous, farsightedness, fundamentals, firepower, fulmination, futuristic, forcefulness, forefathers, futureless, fomentation, felicity, foliated,felonious, ferrying, ferociously, flabbergasting,  forefinger, functionalist, and functionally