Let’s talk about indefinite articles today. The indefinite article in English is used in two versions: A and AN. Choosing one or the other depends on the initial sound of the word that follows. If it’s a consonant, you should use A:
a car, a dog, a city
If it’s a vowel, you should use AN:
an orange, an apple, an elephant
Now, to make things clear, what matters is the initial sound of the word that directly follows the article, not necessarily the noun. So, if there’s an adjective before the noun, our choice of article depends on the initial letter of that adjective. So, you say A DOG, but AN UGLY DOG. Or the other way around, you say AN APPLE, but A GOOD APPLE.
One more thing to keep in mind is that consonants and vowels are what we hear, not what we see. This means that even if the initial letter suggests a vowel, there may actually be a consonant or vice versa.
For example, the first letter in the word UNIFORM is U, which looks like a vowel. But if you look up the pronunciation of this word, it’s /ˈjuːnəˌfoɚm/, so with the initial sound being a consonant. Hence the correct article is A: A UNIFORM.
Here are some more examples like that:
a European /jurəˌpiːjən/ country
a ewe /ˈjuː/
a united /jʊˈnaɪtəd/ front
On the other hand there are words that start with a silent H. This means the first sound you actually hear is a vowel. That’s why you should use AN with such words. Some examples:
an hour /ˈawɚ/
an honor /ˈɑːnɚ/
Finally, you must be careful with numbers written with digits and initialisms. What matters here is how you pronounce them. For example, the number 8 starts with a vowel, so you should use AN:
an $8,000,000 investment – pronounced: an eight-million-dollar investment
Now, if you have an initialism, or even a single letter that should be pronounced like in the alphabet, the choice of article again depends on the pronunciation. So, although the first letter in FBI is F, which is a consonant letter, you pronounce it /ˈɛf/, so AN should be used:
an FBI agent
You should have no problems with indefinite articles now.
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