There are different forms of communication, including:

• gesture (some of which is universal - e.g. "it was this big"; some is culture specific, e.g. "thumbs-up")
• facial expression (much of which is universal, e.g. smiling, looking sad, as per Ekman's research)
• non-verbal sounds (e.g. clearing throat)
• writing (different languages may use symbols for characters, syllables, or symbols)
• speaking

Speaking involves the speech chain:

• [linguistic] the brain of the speaker decides what to say and then sends signals to
• [physiological] the vocal muscles which are involved in speech production, which make
• [acoustic] sound waves, which travel through the air and hit
• [physiological] the ear of the listener, causing stimulation of the audiory nerves, which results in messages being sent to
• [linguistic] the brain of the listener, which attempts to make sense of what has been said

Crystal ch.64 lists Hockett's 13 design features of communication using spoken language - well worth a read.

The written representation of language can vary in the extent to which it represents the spoken form. For example in German, you can get a fairly good idea of how the word sounds by seeing how it's spelled. In English, while this is sometimes true, words like "cough" throw a spanner in the works. In Chinese, symbols are used which represent ideas rather than sounds, and the symbols don't give any clue as to how the corresponding sounds should be pronounced (like "1","2","3", which "mean" the same but are pronounced differently by different language speakers).

Phonetics is concerned with the description and classification of speech sounds. It attempts to describe all the sounds that are made in speech from all human languages. Not all languages use all sounds, e.g. some African languages make use of "clicks" that would not be used by an English speaker (and can only be approximated in written form e.g. "tchk").

The International Phonetic Alphabet (IPA) is one way of classifying the sounds of speech. All human speech can be broken down into a set of individual distinctive sounds, or phonemes (in the same way as written words can be broken down into individual letters). Here is a link to the full IPA chart

Compared to written language, spoken language is capable of conveying a lot of extra information (some of which may be captured in an IPA transcription), for example:

• dialect
• accent
• mood of the speaker
• gender of the speaker
• inflexions e.g. for irony

Useful book readings for this lecture:

• Roach: "Phonetics", ch. 1
• Fromkin: "An Introduction to Language", ch. 6
• Crystal: "Encyclopedia of Language", ch. 27, 64