English as a second language/Pronunciation
The Bio Mechanics of the Human Speech Organs 
You can think of your mouth as an instrument that produces sounds. You use your tongue, throat, lips, teeth, palate to produce sequences of noises that have meaning in English.
IPA Chart 
This chart shows the similarities and differences in British, American, Australian and New Zealand English.
English Phoneme Production 
English Language Timing 
Language timing is the rhythmic quality of a particular type of speech, in particular how syllables are distributed across time. There are two types of language timing: stress timing and syllable timing.
Syllable Timing 
In a syllable-timed language, every syllable is thought to take up roughly the same amount of time when pronounced, though the actual length of time of a syllable depends on situation. Finnish and French are commonly quoted as examples of syllable-timed languages. This type of rhythm was originally metaphorically referred to as 'machine-gun rhythm' because each underlying rhythmical unit is of the same duration, similar to the transient bullet noise of a machine-gun.
Stress Timing 
In a stress-timed language, syllables may last different amounts of time, but there is a constant amount of time (on average) between two consecutive stressed syllables. English, German, Dutch, Italian and Portuguese are typical stress-timed languages. Stress-timing is sometimes called Morse-code rhythm. When spoken faster, a stress-timed language usually shortens, obscures, or drops vowels to carry more syllables between two stresses without changing its rhythm so much.
Origin of differentiation This difference comes from the human's two senses of rhythm. When a human hears a fast rhythm, typically faster than 330 milliseconds (ms) per beat, the series of beats is heard as one solid noise. For example, a human can imitate a machine gun sound, but hardly count its beats. Conversely, when a slow rhythm is heard, typically slower than 450 ms per beat, each beat is separately understood. The speed of a slow rhythm can be controlled beat by beat, such as hand clapping in music.
If a language has a simple syllable structure, the difference between the simplest and the most complicated syllables in the language is not wide, and it is possible to say any syllable in less than 330 ms. This includes languages that have very few consonants in each syllable. Thus we can use the fast syllable-timed rhythm. If a language has complex syllables such as ones with consonant clusters, the difference between syllables can be very wide, such as the words a and strengths in English. In this case, the language has slow stress-timed rhythm.
English Sentence Stress Rules 
Stress Content Words
Content words carry meaning. Content words are:
- Main Verbs
- Negative Auxiliaries
Do NOT Stress Structure Words
Structure words support grammar and are of secondary importance, so they are not stressed. Structure words are:
- Auxiliary Verbs
English allows you to intentionally emphasize what is otherwise a structural word. For example:
- When in yours you can do what you want, but do not smoke in my car.
Meaning that it is not anyone else's car. By changing the normal pattern of stress, you draw attention to this word.
I WANT to HOLD your HAND.
You DIDN'T TELL her the TRUTH.
PLAYing on the ROAD is NOT a WISE CHOICE.
- Wikipedia Stress Timing
- Roach, Peter (1998). Language Myths, “Some Languages are Spoken More Quickly Than Others”, eds. L. Bauer and P. Trudgill, Penguin, 1998, pp. 150-8
- BBC Stress Timing Exercises
- English Club Sentence Stress Exercises
- English Club Word Stress and Sentence Stress Overview
- About English Word Stress Changing Meaning
- English Club Sentence Stress Rules
- How To Pronounce Dates and Numbers in English