The English spelling system is 'absolutely, unspeakably awful'. That is the conclusion of new research that has found that children face 800 words by the age of 11 that hinder their reading because of the way they are spelt.

Monkey, asparagus, spinach, caterpillar, dwarf, banana, handkerchief, pliers, soldiers, stomach, petal and telescope have all been included on the long list of words that baffle children because they contain letter combinations that are more commonly pronounced in a different way.

The words have all been identified as problematic for reading, as opposed to writing, because of their 'phonic unreliability', according to the study The Most Costly English Spellings. It was presented yesterday at the conference of the Spelling Society, held at Coventry University. Masha Bell, the literacy researcher who carried out the work, argued that there were 200 words on the list that could be improved by simply dropping 'surplus letters' such as the 'i' in friend or the 'u' in shoulder.

'English has an absolutely, unspeakably awful spelling system,' said Bell, a former English teacher and author of the book Understanding English Spelling. 'It is the worst of all the alphabetical languages. It is unique in that there are not just spelling problems but reading problems. They do not exist anywhere else.'

Bell argued that the spelling system was a huge financial burden on schools and was to blame for poor literacy results compared with the rest of Europe. In Finland, where words are more likelyto be pronounced as they look, children learn to read fluently within three months, she said. In the UK, academics have found that it takes three years for a child to acquire a basic level of competence. The tricky spellings make English particularly difficult for children with dyslexia and those from disadvantaged families, who are less likely to be read to regularly by their parents.

In the research Bell highlights examples of words that have the same pronunciation but different letter combinations. Examples include to and two; clean and gene; same and aim; day and grey; kite and light; and stole and coal.

Then there are those that look alike but sound different with the combinations of 'ea', 'ee' and the letter 'o' causing most trouble. Among the words falling into that category are eight and height, break and dreamt, and move and post. The letters 'ough' can also be pronounced in a number of different ways.

Simplifying the system would transform literacy results, according to Bell, but she said people were resistant to change. 'People feel that they have suffered so much at the hands of English spelling that they are reluctant to look at it,' she said. Yet other countries have made changes. Last month the parliament in Portugal, where the spelling system is also thought to be complicated, voted to reform and simplify it, bringing it into line with Brazil.

'In 1928 the Turks changed their entire alphabet from Arabic to Latin,' said John Wells, professor of phonetics at University College London and president of the Spelling Society. 'It happened in the Soviet Union.' In Germany there were changes made in the 1990s to make the writing system more consistent. English has also developed with words such as 'olde' and 'worlde' dropping the 'e'.

Wells wants to see things change again and feels there are two possible approaches. The first would be to simplify the way in which words are spelt and then allow people to choose whether to use the new or old system, while the second approach would involve a complete change. 'The Spelling Society favours the first,' he said.

Chris Davis, spokesman for the National Primary Headteachers' Association, said the spelling system had a major impact on children's literacy progress: 'It definitely slows English children down. In international comparisons, languages that are phonetically uniform always come top.'

But he said that teachers would be reluctant to see things change. 'It would be such a major revolution that people would find it very difficult to contemplate,' he said.

'There are already problems because of the different spelling system in America, but there would also be resistance about going down that route. I think it is an ownership thing, that it is our language.' Davis argued that people felt that spelling was linked to the origin of words.

100 of the most difficult words

Orange, foreign, rhinoceros, properly, vomit, tambourine, tournament, tourist, heaven, engine, exquisite, opposite, advertisement, gnarled, rigid, risen, sinister, spinach, video, vinegar, tie, wheelie, quiet, science, crier, pliers, soldier, Monday, mongrel, monkey, courage, magic, manage, palace, four, journey, gnash, gnaw, gnome, ghastly, guard, miracle, miserable, pigeon, pity, prison, month, mother, nothing, once, smother, son, sponge, tongue, wonder, almost, both, comb, ghost, gross, most, only, post, programme, deny, reply, July, obey, caterpillar, chapel, damage, dragon, fabulous, family, famished, garage, glacier, habit, hazard, hexagonal, imagine, panic, radish, miaow, powder, cauliflower, plant, pyjamas, raft, rather, salami, task, vast, kiosk, kiwi, machine, encourage, somersault, swollen, souvenir.