When listening to native speakers they do not seem to say one hundred or one kilometre properly. The 'one' sounds more like an 'er' sound. Can you please explain to me why this is and if I should try to do it too?
Malgorzata J., Warszawa.
How nice to have a letter from a student with a good ear! Language is all about sounds but is usually taught in school from books, so it is only too easy to look at the letters rather than listen carefully to the sounds. And this distinction is most important in English, where the sound of the word, and the letters used to write the word, are often very different.
Consider the words 'one', 'once' (one time), and 'only' (one instance). These words are clearly linked in meaning, and in their history, but the last sounds completely different to the first two. The reason is that the pronunciation of the words has changed a lot over time, whereas the spelling has not changed so much.
Now it was the word 'one' that you asked about, and the history of its use gives us the answer to your question.
The word for '1' in Early English was 'an' pronounced with a long 'a' (in fact in Scotland and the North of England many people say 'ane' (to rhyme with 'pain') for 'one' even today.) When talking about a single countable thing, people said 'ane apple' or 'ane priest', in the same way as the French and Germans used their word for one; 'un' or 'ein'. But the French and Germans still use the count word as the indefinite article. Only in English has a change taken place.
Now 'ane apple' is quite easy to say, although the modern version is a shorter sound: 'an apple,' However 'ane priest' is rather more difficult, so the 'n' has been dropped in front of words beginning with a consonant, so today we say 'a priest, a church, etc'. However, this little sound 'a' is very soft and never stressed, so quite unsuitable as a count number. Therefore 'an' became 'one' (with a pronunciation copied from French - think of the French word for 'yes', 'oui' and you see where the 'w' sound for the written letter 'o' comes from. Remember England was a French-speaking country for over 200 years after the Norman Conquest).
So one word became three. 'Ane' became 'a' for use as an indefinite article, as in 'a church'; 'an' when used as an article in front of a word beginning with a vowel sound, as in 'an apple'; but 'one' if used when counting, as in 'one, two, three.'
But imagine this bit of conversation:
"Professor, how many letters from readers do you get each year?"
"About a hundred, I suppose."
"Did you say two hundred?"
"No! I said one hundred."
You will have noticed that that your dear Professor, who always tells the truth, says "I said one hundred", whereas he actually said 'a hundred'. In other words, to an English speaker the words 'a', 'an' and 'one' are still the same word, but with just different degrees of emphasis!
If I wish to stress that there was only one other person in the cinema when I went to see a film, I would say "There was only one other person there." But "I saw a film in an almost empty cinema", not *"one film in one almost empty cinema"*. We use the form 'one' for counting and for stress, but the sentence "1000 people gave L1 each to the charity" would be read by any native speaker as "A thousand people gave a pound each to the charity". Only if the number one requires to be emphasized, like if it might be misheard, is the stressed pronunciation 'one' used.
A similar story could be told about the definite article, 'the'. 'The' is used in English before a noun which is unique (as in 'the Queen', 'the moon') or which has already been identified (as in 'This is the book I told you about'). Now to identify nouns, we can use the words 'this' or 'that' - but usually only when pointing physically: "This book is better than that one". Consider the statement "The book I am reading today is better than the book I was reading yesterday". I could have written "This book I am reading today is better than that book I was reading yesterday". Why didn't I, as both sentences are correct and mean the same thing? The answer is that I did not need to stress 'this' or 'that', so just used the weak form of the article, 'the'. For if we looked back to Early English, we would find that 'the' and 'that' were the same word!
I think you will find that having identified these two 'word families' - (a, an, one) and (the, that, this) - this will help you to know when to use articles, and which ones to use. Since that is a problem for all speakers of Slavic languages such as Polish (I do not ask for 'jeden bilet' at a railway station, but I do have to say the equivalent in all western European languages): anything that helps you get articles right is very useful indeed. So I'm very glad you asked your first question. And to answer your second one - Yes. Try to speak like the natives. These sound changes have only happened because it makes speaking English easier - and makes understanding what you say easier too. These 'weak forms' of common words are very important in spoken English - but that is a topic I shall return to in a future issue.