What are vowels in English grammar? How to use "a", "an" and "the" in front of words? Why do we say "half an hour" (h is not vowel). Which one is correct a English teacher or an English teacher?

1.  Vowels are the sounds that are used to help pronounce words easily. In some arabic script, the main written vowels are 'dhabr, dher and pesh' allowing you to know whether the sound is an 'aaa', 'eee' or 'ooo' sound.

2. 'A', 'an' and 'the' are known as articles. 'A' and 'an' are used for indefinite articles, for example, if you're referring to random objects, places or people e.g. a boy, a house, an apple. 'A' is used when the subject starts with a consonant (letters other than a,e,i,o,u).  'An' is used before a word that starts with a vowel. 'The' is called a definite article when you're refering to something specific e.g. The boy has a dog. It's not any boy, it's a particular one. From your question,  'An English teacher', is correct for2 reasons; An is used for a random English teacher, and 'an' because 'English' starts with the vowel 'e'.

3.' Half an hour' uses the pronunciation rule. When the word is said out loud and it sounds like it starts with a vowel  we use 'an'. 'Hour' is pronounced as 'our' so we use 'an' before it.

I hope that helps :)

Oh my God ))) Who asks such strange qsts? Students? Kids? Vowels are: a, e, i, o, u , y

H is not read in some words, like in hour or honest or heir, this an hour

An English teacher, as E is a vowel, thus an

I don't agree with some parts of the answers given above:

1. Vowels: Vowels are those sounds where we don't feel any obstruction in our mouth while producing it. For example: /i/, /i:/ /a/ etc . In producing /i/ sound our lips are apart and we don't feel any obstruction when the air is coming out of the mouth. There are twenty vowel sounds in English.

On the other hand, Consonants are those sounds when we feel obstruction in our mouth while producing it. For example: /b/. In producing /b/ sound our lips combined together and create obstruction of air while coming out of the mouth. There are 24 consonant sounds in English.

2. There are two types of articles: (i) Indefinite Article and (ii) Definite Article  

• "A" and "an" are called indefinite articles because they are put before indefinite noun. For example: "a doctor" means "any doctor" or "an elephant: means "any elephant".
• "The" is called definite article; because it is put before a particular noun which under discussion or already known in a discussion. For example: "the doctor we met was a good person." "The elephant we saw at the zoo was big."

3. I don't agree that there is any exception in case of "a" or "an" putting before noun because "an" is only put before vowel sounds. And "a" is put before consonant sounds. 

• in "half an hour" ---the sound of "hour" begins with "a" sound. An other example may be: an MA; or such opposing examples may also be found: a university.....

Thank you for the invitation I agree with the experts answers

Vowels, consonants and diphthongs are classification of sounds, not of letters. English alphabet has 26 letters (A-Z) but the language has 44 sounds - 24 consonants, 12 pure vowels and 8 diphthongs. The sounds that are produced with obstruction in the vocal tract are called "consonants." p, t, k, g, f, l, etc are consonants because we cause obstruction (i) by closing lips to produce p, (ii) touching hard palate by tongue to produce t, (iii) touching soft palate by back of tongue to produce g, (iv) touching lower lip by upper teeth to produce f, (v) touching teeth ridge by front part of tongue to produce l. In contrast, sounds that are produced without obstruction anywhere in the vocal tract are called "vowels." For example, there is no obstruction when we say the sound represented by the letter a. There are two semi-vowels in English, sounds represented by letters y and w. Semi-vowels are similar to vowels but function as consonants. That's a technical issue, so ignore it at the moment. Diphthongs are a combination of two vowel sounds, and a lot of words use them. Words like, so, no, oil, boy, flight, etc have diphthongs. Let's put aside diphthongs because they are not important to understand the use of articles (a, an, the are called articles in English). If a word begins with a vowel sound, and we need to use an article before it, we use 'an.' For example, an umbrella, an apple, an instrument, etc. If a word begins with a consonant sound, we use article a. For example, a house, a dog, a car, a man, etc. The meaning of A/An is "ANY," not a particular thing. (You may consider a/an as short forms for "any.") In contrast, if we talk about a particular object, we use article 'the' with it. For instance, if we talk of something for the first time, we use 'a' or 'an,' but on a second reference of the same thing requires the use of 'the.'  A very common example found in grammar books is from stories, like this:

Long ago once upon a time there lived a king in France. The king was very cruel.

Uses of 'the' are multiple. Here I have given its use in contrast with a/an. You may consider 'the' as a short form for this/that because as this/that indicate a particular thing (not "any" thing in general) "the" also indicates a particular object. Like in the example given above "The king"  means "that king which I have just now told you about...." 

From the discussion above it must be clear that 'h' in English is a letter, not the exact sound. In the word "hour" it doesn't represent the sound 'h' but rather it stands for the sound a (we cannot write the correct pronunciation of 'hour' using English letters, but an approximation is au(r)), so it begins with a vowel sound; that's why 'an hour.' 'An English teacher' is correct because the word 'English' begins with i (called short e) which is a vowel sound. 

thanks invite. ......Support answer experience 

I agree with specialties answers, thanks for the invitation. 

The provided answers, so far, have given a clear idea about the topic. I have nothing new to add!

1. vowels are the sounds A.I.O.E.U as well as any other sounds pronounced in the same way ( Y or W or H in some cases ).

2. articles are devided into two divisions. A- definate article ( the ) , B- indefinate article ( A, An). definate article is comming when we talk about specific things. E.X: you must read the book ( interlocuter knows what book do i mean ) , but; indefinate articles come when speaker speaks about inspecific  book (thing). so we knew that A.A comes in the same case ane the in other case but the question here is what is the difference between A and An?. well; the difference is that when article is followed by vowled sounds we here use An, but if it is not here we use the article A.

3-We say half an houre becouse the article here is followed bu vowel sound ( when H sould comes at the beginning of the word). see point number 1.

4- the correct is An english teacher, becouse; the articles followed by vowel sound E.

5- we do not use any articles when we speak about things in general. E.X: I love gamming , see that you do not talk about specific type of gamming ( football of car racing .. etc) so we did not use any articles as we are talking about thing in general.

First of all vowels is in English language is "a, e, i, o, u" these are vowels, when a word start from these vowels so we will use an otherwise normal a. so we can say that an English teacher in the above question