phoneme: A phoneme is the smallest contrastive unit in the sound system of a language.
Example: the sounds /t/ and /d/ are represented by the letters t and d are two english phonemes. The word cat contains three phonemes /c/ /a/ /t/.
What is the the big deal about phonemes?
Phonemes are small units of sound produced, combined and processed seamlessly in our brains in order to create language. As humans evolved we created ways to represent language in a written form. Written language evolved from pictures representing words. Pictures could easily represent nouns and other concrete words. Then the pictures evolved to represent syllables, or parts of words in order to accommodate more abstract linguistic concepts. The Sumerians were the first to break the syllables into individual phonemes and represent them with pictures thousands of years ago. As these pictures became more abstract their representation evolved into letters. The birth of our alphabetic system of written language was built upon these tiny phonemes.
It is good to be aware of the phoneme
Our English language consists of 44 phonemes that are represented by 26 letters. This combination is the basis of all reading and written language. Reading research proves that there is a link between a student's ability to isolate individual sounds within words and their ability to learn to read. This skill is called phonemic awareness. In 1974, University of Connecticut professor Isabelle Y. Liberman publishes ‘Explicit syllable and phoneme segmentation in the young child’ which is an influential paper regarding reading acquisition. Now phonemic awareness is identified as one of the 5 big ideas in reading by the University of Oregon as a crucial part of learning to read.