Phonetics.

According to some experts, Phonetics is a branch of Linguistics that studies the sounds of human speech, applied also in sign language to look for its equivalent in sound. Phonetics is concerned with the physical properties of speech sounds of signs, their physiological pronunciation, acoustic properties and perception.

Phonetic Transcription.

The International Phonetic Alphabet (IPA) is used as the basis for the phonetic transcription of speech. These symbols are based on the Latin Alphabet, which is able to transcribe most of the speech sounds, such as consonants, vowels and suprasegmental features. Every known phoneme has a determined symbol.

As you can see in this image, these are the English vowels, making a total of twelve (I was surprised when I've heard it the first time, because in Spanish, we only have five). What do this chart represent? The position of the vowels! Every vowel resonates in our oral cavity, in a different position and in a different mouth position! for example, when you pronounce the "i" vowel, your mouth is not open but not entirely closed, and when you pronounce it, you can feel how your voice sounds at the front of your vocal cavity, that's why "i" is in a frontal position with your mouth closed (not so much as closed...)

Something else I might forgot? Post it!