When we first learn to read aloud, we try to articulate the sound which each letter makes. We soon learn that there is a difference between a vowel, which requires a steady stream of breath, and a consonant, which momentarily stops the flow in one of a number of ways. Generations of pre-school children have grown up learning the letters associated with these sounds by chanting mantras such as 'cuh is for cat, duh is for dog'.

When we combine a consonant with a vowel we make a simple syllable, the basic building block of language, and by combining these we start to construct our vocabulary of words.

For more complex sounds we can combine consonants, but mastering the pronunciation of these can take a little practice. Some trip off the tongue quite naturally: FR in 'friend', or BL in 'blue', for example. Yet, if you look hard enough, you'll find obscure words with very peculiar opening combinations. Some are a throwback to archaic forms of English. Others are imported from foreign languages. All present a challenge to pronunciation.

This Entry unearths a few of the rarer, uglier consonant combinations from the dark recesses of the Oxford English Dictionary (OED). The rarer the word, of course, the less likely we will ever need to vocalise it; indeed, we do not know exactly how some of the older words were pronounced. The opportunities to drop these into everyday conversation may not always be straightforward, but, if nothing else, they could well solve a problem or two with a bad Scrabble rack. So, without further ado, let's crack on with the cruel consonant combos.

BD is for Bdellium

The fragrant-resin-producing biblical shrub, the bdellium was first recorded in English in 1398. The OED advises us to pronounce it with a silent B, as you would do with the other two BD- words, bdellatomy (a surgical incision into a leech) and bdellometer (a blood-drawing surgical instrument).

CHTH is for Chthonic

Deriving from Greek, the chthonic or chthonian gods were those who dwelled below the surface of the earth, as opposed to the celestial ones in the heavens. The opening combination is pronounced 'kth-'.

A similar combination exists in PHTH- words, for example phthalates, a group of chemicals used in the manufacture of soft plastics. The opening PH is an optional F- sound in front of the TH (but is not pronounced in American English). An archaic term for tuberculosis is the word phthisis, which is similarly pronounced '(f)thigh-sis', but this one benefits from a simpler alternative 'ty-sis'.

CN is for Cnida

You've suffered enough from this word already if you've ever been stung by a jellyfish. The cnida is the zoological name for its stinging cell (plural cnidae). It may have been the inspiration for the 'Vermicious Knids', described as the enemies of the Oompa-Loompas in the 1971 film Willy Wonka & the Chocolate Factory¹.

Other CN- combos include the anatomical word cnemial, meaning 'related to the tibia', and cnicin, a chemical obtained from some plant leaves. In many of these, you must pronounce both a hard C and the N together, although in some words like Cnidaria (the zoological phylum which includes jellyfishes) the C is optionally silent.

The unusual mathematical term cnicnode, coined by Arthur Cayley in 1869 and meaning 'a conical point', has two CN combinations. It is pronounced with the first C silent.

CT is for Ctene

Derived from the Greek word for 'comb', the ctene is the plate of fused cilia along each side of a comb jelly, with which the creature propels itself through water. The creatures are known as ctenophores, and indeed anything comb-shaped can be described as ctenoid. The C is silent in each case, so ctene is pronounced exactly like 'teen'.

There is also a single KT-word, ktypeite, a variety of crystallized lime carbonate. The K is silent.

DGH is for Dghaisa

One of the few Maltese words to enter English, the dghaisa is a gondola-shaped boat. The G and H are silent, and the whole word is pronounced like 'dicer'.

DS is for Dso

What do you get if you cross a yak and a cow? Plainly you get the dso, a Tibetan beast of burden. It's also spelled 'zho' (a truly wonderful Scrabble word). This latter form is pronounced with the 'zh' sound being like the French 'j' in 'je', but sadly we have no standard form of pronunciation for 'dso'.

DV is for Dvorakian

The Sanskrit-derived word dvandva is a grammatical term, indicating a particular type of compound word. Both D and V are pronounced throughout the word.

A perhaps more common DV word in the OED is Dvorakian, describing music characteristic of the Czech composer Antonin Leopold Dvorak (1841–1904). You might describe music on classic TV bread commercials as Dvorakian, especially if it accompanies a boy pushing a bike up a very steep hill. In terms of pronunciation: the D is optional. Oh, and there's an unannounced 'zh' sound after the R.

FJ is for Fjord

When a J follows a consonant, it often indicates a Scandinavian-derived word. The most common must be fjord, the coastal feature which gives Norway's map its distinctive (and award-winning) crinkly edges. Pronounce the J as a Y and you won't go far wrong with this, neither will you with more obscure words like gjetost (a Norwegian goat's-milk cheese), Hjelmslevian (characteristic of the work of Danish linguist Louis Hjelmslev), and kjerulfin (a type of rock named after Norwegian mineralogist Professor Kjerulf).

FN is for Fnarr Fnarr

The sniggering sound suggestive of sexual innuendo, fnarr fnarr is a very recent addition to the OED. Both F and N are pronounced, but we aren't given a guide to pronouncing the other two FN-words, as they're both obsolete: fnast (to snort) and fnese (to sneeze).

GM is for Gmina

Polish local government officers will be familiar with the gmina, an administrative sub-district. The G is silent, but it isn't in the only other GM-word, Gmelinite, a mineral named after a Professor Gmelin in 1825.

GN is for Gnu

One of the most widely mispronounced English words must be the South African quadruped we call the gnu. The G is silent - it's not even optional - yet this hasn't stopped the spoken G from creeping in to popular culture. One pair of culprits were musical comedy duo Flanders and Swann, who popularised it in their song 'The Gnu':

I'm a gnu, I'm a gnu
The g-nicest work of g-nature in the zoo...

It's unclear why we mispronounce 'gnu', as almost every other GN-word has a silent G, and many of these are common, like gnome, gnat and gneiss (pronounced 'nice'). Two we should watch out for, however, are the German-derived gnädig , which has a hard G, and the Italian dumplings called gnocchi ('nyocky').

HW is for Hwyl

There's something in the identity of Welsh people which inspires emotion and impassioned eloquence in them when they gather together, especially at the National Eisteddfod, their annual cultural festival. This something has a name, and it's hwyl. Deriving from Welsh, the W is not strictly a consonant - it's a vowel with an 'oo' sound - so we pronounce this a little like 'hoo-ill'.

If you've a Scrabble rack without any vowels whatsoever, then a Welsh W can often come to your rescue, as we see in words such as cwm (a glacially-formed hollow) and crwth (a Celtic violin). We pronounce these as 'koom' and 'krooth' respectively.

KG is for Kgotla

A number of words which open with combinations of consonants have been imported into English from African languages. In each case, all consonants must be pronounced. There are many examples, including the Bantu meeting of tribal elders known as the kgotla, the Angolan coin the lwei ('luh-way'), the Zulu political stooge mbongo, and the respectful form of address Ntate.

KN is for Knish

Learning English for the first time, a native French speaker may pronounce knew more like 'canoe' than 'new'. This tendency was ridiculed in the film Monty Python and the Holy Grail, in which the French castle guards proudly pronounce every consonant from the word knight ('kuh-nigget').

Now, we all know that the K from KN is always silent, but is it? It is said that in Shakespeare's day, the K was always pronounced, and today we have a few imported words in which it still is. Yiddish has given us the delicious-sounding fried cake, the knish, and from German we have the knödel dumpling.

MN is for Mnemonic

Sadly, there's no simple way to remember how to pronounce consonant combinations. If there were such a method, we might call it a mnemonic, one of a number of words derived from the Greek word for 'memory. In all cases, the initial M is silent.

NR is for Nritta

Sanskrit words often present some interesting combinations, but the general rule is to pronounce every letter. Nritta is a rhythmic form of Indian dance. We also have a JN-word: jnana is the spiritual knowledge which devout Hindus seek as the path to salvation.

PN is for Pnicogen

Most opening combinations beginning with PN, PS and PT have the letter P as silent, and we're all familiar with common words such as pneumatic, psalm and pterodactyl where this is the case. However, dig a little deeper and you'll find the odd exception, like pnicogen (any element from group 15 of the periodic table), pschent (an Egyptian headdress crown), and ptish (an exclamation of contempt).

SB is for Sbirro

It's quite common in Italian to prefix a word with a very unnatural-looking S, and a few of these have been imported over the years. Sbirro, a police officer, is pronounced 'zbirro'. Other more common words of this type include sforzando, a musical instruction meaning 'forcefully', and sgraffito, a method of decoration in which a plaster surface is scratched to reveal another colour beneath . These latter two pronounce the S as you would expect.

TL is for Tlachtli

One reason the Mexicans are good at football could be that they are descended from Aztecs who played the ceremonial ball game known as tlachtli or tlaxtli. Every letter of 'tlachtli' is pronounced, making this quite a mouthful. The Maya also played the game, but gave it the far more pronounceable name of pok-ta-pok.

TM is for Tmesis

A tmesis is a grammatical construction where a word or phrase is split in two and another word inserted into the middle. It's most commonly used today for emphasis, when the inserted word is often some sort of expletive, for example 'abso-bloody-lutely!'. It derives from a Greek word meaning 'a cutting', and both T and M are pronounced.

TP is for Tprw

Three gloriously unpronounceable TP-words exist, and so shall they remain, as the dictionary has recorded them as obsolete. All three are cries: tphrowh calls for attention, tprot is an expression of contempt, and tprw somehow imitates the sound of a horn.

WL is for Wlonk

A group of obsolete Old English words begin with WL, yet sadly we have no idea how to pronounce them. Some are described elsewhere in the Entry on the word wlonk, meaning 'a fair or beautiful one'.