Phonology and phonetics.
Our perception of language is frist of all a sensory perception. We hear it or we see it. However, we seldom reflect on what we actually hear or what we actually see. Usually we are too busy interpreting the meaning of what we hear and what we see think about the actual sounds or the actual shapes we are perceiving. Usually, it is only when we hear or see language in a foreign, unknown togue, or alphabet that we become conscious of individual sound or shapes that compose the language text. In such a situation we cannot understand the meaning, and the brain can give its undivided attention to the pure experience of sound as symbol.
One of the distinguishing characteristics of literary texts is the way in which they manipulate their sounds or letters. In ordinary texts we expect sound and symbol to be transparent to meaning. But in literature it often happens that the sounds or symbols of the medium become important in themselves. There are not there just to encode a meaning- their peculiar arrangement constitutes part of the meaning of the text. In losing their transparency, they become objects of attention. We are fotced to reflect on the features of the medium of language,not just on the meaning which the medium conveys.
We are considering only the sounds of language. There sounds are already familiar to you as "consonants" and "vowels" . Taken together we call these the"segmental" sounds, because each consonant and vowel constitutes one small segment of the whole spoken text. The term "phonology" refers to the way in which language is encoded in its medium as sound. The term" phonetics" refers to the way in which individual sounds are formed by the apparatus of speech, or detected by the apparatus of hearing.