My previous article about the phonetic alphabet (A for alpha, B for bravo, C for Charlie) reminded me of a game I call Telephoneys or Crossed Lines, where you think of words that can deliberately mislead someone when you are spelling out names or words on the telephone.

For instance, if your surname is Page and you want to clarify it for someone you are talking to, you can say “P as in pant, A as in alpha, G as in golf, and E as in echo”.

However, if you want to be really unhelpful, you could say “P as in phew. A as in aisle, G as in gnaw, and E as in ere”.

When I set this as a problem in my book Oxford Word Challenge, I managed to supply nearly a full alphabet of these misleading words. The letters F, L, N and R proved difficult but the remainder were: aesthetic, bdellium, cue, djinn, eye, gnosticism, honour, impasse, Janacek, knee, mnemonic, ouija-board, pneumonia, quay, see, Tchaikovsky, urn, Vaterland, why, xylophone, you and zarzuela.

If you wanted a word with a silent L at the beginning, you might use Welsh words that start with a double L, like Llanfair, the Lleyn Peninsula, or Llanfairpwllgwyngyllgogerychwyrndrobwllllantysiliogogogoch, which are all place-names pronounced something like thl- or chl-.

If you allow silent letters in the middle of words, you could solve F, L, N and R by using halfpenny for L and F, damned for N, and forecastle for R.

Hergé’s famous Adventures of Tintin include a couple of clueless detectives called Thomson & Thompson (Dupond & Dupont in the original French), who were notorious for trying to distinguish themselves from one another by giving misleading clues to their names. Thompson tends to say things like “Thompson with a P, as in psychology (or Philadelphia)”. In The Seven Crystal Balls, the other one, speaking on the phone, says: “This is Thomson . . . no, without a P, as in Venezuela”.

The phenomenon of unsounded letters has intrigued people for a long time. Silent letters account for many of the spelling mistakes made by British speakers (e.g. how many Cs and Ms are there in accommodate?). They also cause dilemmas for foreigners trying to learn English.

In fact there is a huge number of English words containing unsounded letters. Many of these occur in common collocations. For example, the G is usually silent when it precedes an N, as in gnash, gnat and gnaw. Flanders & Swann made a comic song out of this phenomenon by deliberately pronouncing the G in ‘I'm a G-nu’.

Similarly the K is usually silent when it is followed by N, as in knee, knife, know and knight. The last two of these words suggest why silent letters can sometimes be useful, because the K in know makes it different from the similarly-pronounced no, and in knight the K distinguishes it from night.

In fact at one time the K in knight was sounded, so that the word was pronounced something like k-nicht.

Why are there so many silent letters in English? The main reason is that we speak a mongrel language: a mixture of words from Anglo-Saxon, Greek, Latin, French and many other languages.

For example, there is a superfluous C and M in accommodate, because we borrowed the word direct from Latin. There is a spare letter A in bazaar, because we took the word from Persian.

The silent M at the beginning of mnemonic exists because the word originally came from Greek. Numerous words starting with P were borrowed from Greek (often via Latin), giving us the unsounded initial in pneumonia and psychology. The RH and RRH in rhetoric, rhythm, catarrh and diarrhoea come to us from Latin.

Ptomain actually comes to us from Italian, although it derives ultimately from Greek ptoma, which means a corpse.

Spelling did not start to be standardised until the introduction of printing in the 15th century, before which people spelt words as they heard them. Even Shakespeare’s name was spelt in many different ways, including Shakspeare, Shagspere and Shaxberd.

As spelling began to be regularised, some smart-alecs inserted unnecessary silent letters such as the GH in delight (which was originally spelt delit in Middle English) and the S in island (spelt iland in Middle English) — both on false analogies with light and isle.

If you are really looking for confusing silent letters, try some English place names — like Towcester, Worcester, Colne and Greenwich. The East Anglian village of Happisburgh is pronounced haze-brer, while the Scottish town of Milngavie is pronounced mull-guy or mill-guy. Even more potentially confusing are such surnames as Dalziel (as in Dalziel & Pascoe), Pepys, Featherstonehaugh and Colquhoun!

Tony Augarde is the author of The Oxford Guide to Word Games, The Oxford A to Z of Word Games and Oxford Word Challenge.