1. The Subfields of Linguistics(Human Language Study)

1.1. Phonetics & Phonology

Phonetics: is the study of the production, transmission and reception of speech sounds, which are the smallest units of speech ("phonemes").
Phonology: is the study of sounds and sound patterns of a specific language. It studies the function of speech sounds in language in general or within a given language in particular. It involves the study phonetics.

The Difference between Phonetics and Phonology
        Phonetics studies the nature of speech sounds (their description, comparison and classification); whereas phonology studies the function of speech sounds of language in general or within a given language in particular. This means that phonetics deals with the physical production while phonology deals with sound patterns and meanings.


The Organs of Speech
        The main organs of speech are: the lips, the teeth, the alveolar ridge, the tongue, the hard palate, the velum (soft palate), the uvula, the pharynx, the larynx, and the vocal cords. The active organs are: the lips, the tongue, the velum, the uvula, the pharynx, and the vocal cords. The tongue is so important in the production of speech sounds and it is divided into four areas: the tip, the blade, the front, and the back.

        Most sounds are made with an air stream expelled from the lungs. The air goes up from the lungs to the trachea and into the larynx. Inside the larynx are the vocal cords which consist of two bands of muscle and elastic tissue lying opposite to each other. They can be drawn together or parted. Sounds produced when the vocal cords are brought together and vibrating are called "voiced": /b/,/d/,/g/,/z/,/m/,/i/ . When the vocal cords are apart, sounds produced are called "voiceless": /p/,/s/,/t/,/k/.
Vowels and Consonants

         Sounds can be divided into two main types: vowels and consonants
a/ Vowel: is a speech sound in which the air stream from the lungs is not blocked in the mouth or throat (needs an open air passage in the mouth ), and which is usually pronounced with vibration of vocal cords .
b/ Consonant: is a speech sound with or without vibration of vocal cords where the airstream from the lungs is completely blocked, partially blocked, or where the opening is so narrow that the air escapes with audible friction.
c/ Consonant Clusters: are combinations of two or more consonants one after the other in a word. Most consonant clusters are only three or four letters long. The combination of consonants can occur in initial position at the beginning of the word eg : sprain(cccvvc), or in final position at the end of the word such as : depth (cvccc).

Suprasegmentals
      There are many phenomena that interest the linguist. The most significant of these are: pitch, stress, tone, intonation, and tempo. They are called suprasegmental features, which are concerned with speech sounds and features of the complete speech rather than individual sound.

Pitch: is the melodic height of an individual’s speech.
Stress: refers to the syllable that receives most emphasis.
Languages are divided into two types “syllable-timed” languages like French or Arabic and “stress-timed” Language like English.
Intonation: has relation with pitch and it involves the speech melody over an utterance. The simple statement in English involves fall but a question involves a rise in pitch.
Tempo: is also called speed of an utterance. It is associated with the speaker’s frame of mind. Speed may increase or decrease suggesting excitement or boredom.