Each of the vowel letters (A-E-I-O-U) has a Long-vowel sound, plus one or two Short-vowel sounds, and those are the normal sounds for each vowel. But what does Long-vowel or Short-vowel mean?

Long-vowel

• The Long sound for any vowel, is the same as the name of the vowel letter (like when you say the alphabet). So for example, the sound of Long-A is “A”.
• The label “long” does not mean that it takes a longer amount of time — it means that the vowel sound has two parts. If you look at the International Phonetic Alphabet (IPA) symbols for these sounds, you can see the two parts. For example, the IPA symbol for Long-A is /ey/.
• To pronounce a Long-vowel correctly, the tongue needs to move, or slide, in order to say both parts.
• When making Long-vowel sounds, the tongue will be tense, not relaxed, because the tongue muscle needs to move.

Short-vowel

• Short-vowel sounds have just one part.
• The tongue is still — it does not move.
• The tongue is relaxed.

Using the Long and Short-vowel system

Learning to think in terms of the Long and Short-vowel sounds can be very useful. Here are a few examples of ways the system works.

• Long and Short-vowels often alternate when word forms change. For example: “nature” uses the Long-A sound but “natural” is pronounced with Short-a; “meet” has Long-E but “met” has Short-e; “five” has Long-I and “fifth” has Short-i.
• Different English accents sometimes vary between Long or Short-vowel sounds. For example, the word “tomato” is usually pronounced with Long-A in American English, but in British English it is usually said with Short-a-2, “tomato”.
• Native speakers of English use the Long and Short-vowel system (often subconsciously), when they want to figure out how to pronounce a new word that they have never heard or seen before.
  

  To demonstrate this, I looked for a list of words that are rarely used in English, to find one I had never seen — I found the word “b-r-o-n-t-i-d-e”. My first guess for how to say it was “brontide” with a Short-o, but I also thought it might be said with Long-O, “brontide”. Then I checked to see which was right — my first guess was correct: “brontide”.

  This is the process native speakers often use when they need to figure out how to say a new word.

• Some spelling patterns correspond to Long and Short-vowels. The most basic one is [-e] at the ends of words which indicate a Long-vowel pronunciation. For example, “fat” is pronounced with Short-a-1, but when an [-e] is added, the word becomes “fate” with Long-A, and the word “pin” has a Short-i, but “pine” has a Long-I.

Learning to think of the English vowels according to the Long and Short-vowel system, is a good first step toward learning to use English more like a native speaker does.