Rules for Sentence Stress in English

The basic rules of sentence stress are 

content words are stressed

1. structure words are unstressed
2. the time between stressed words is always the same

The following tables can help you decide which words are content words and which words are structure words

Content words - stressed

Words carrying the meaning	Example
main verbs	SELL, GIVE, EMPLOY
nouns	CAR, MUSIC, MARY
adjectives	RED, BIG, INTERESTING
adverbs	QUICKLY, LOUDLY, NEVER
negative auxiliaries	DON'T, AREN'T, CAN'T

Structure words - unstressed

Words for correct grammar	Example
pronouns	he, we, they
prepositions	on, at, into
articles	a, an, the
conjunctions	and, but, because
auxiliary verbs	do, be, have, can, must

Exceptions

The above rules are for for what is called "neutral" or normal stress. But sometimes we can stress a word that would normally be only a structure word, for example to correct information. Look at the following dialogue

They've been to Mongolia, haven't they
"No, THEY haven't, but WE have 

Note also that when "be" is used as a main verb, it is usually unstressed (even though in this case it is a content word)

Common Reduced Forms in American English

 Going to is pronounced GONNA when it is used to show the future. But it is never reduced when it means going from one place to another 

We're going to grab a bite to eat. = We're gonna grab a bite to eat 

I'm going to the office tonight. = I'm going to the office tonight 

 Want to and want a are both pronounced WANNA and wants to is pronounced  

WANSTA. Do you want to can also be reduced to WANNA 

I want to go for a spin. = I wanna go for a spin
 

Do you want a piece of cake? = Wanna piece of cake 

He wants to avoid rush hour. = He wansta avoid rush hour 

 Have to is pronounced HAFTA and has to is pronounced HASTA 

Sorry, I have to leave now. = Sorry, I hafta leave now 

She has to go to work soon. = She hasta go to work soon 

 Have reduces to AV or A in positive and negative phrases

must have = must'av or must'a 

 must not have = mustn'av or mustn'a
 

would have = would'av or would'a  

would not have =  wouldn'av or wouldn'a
 

could have = could'av or could'a  

could not have = couldn'av or couldn'a
 

should have = should'av or should'a  

should not have = shouldn'av or shouldn'a

 You is almost always pronounced YA  

you're and your are pronounced YER 

and yours is pronounced YERS 

Do you feel under the weather? = Do ya feel under the weather
 

You're completely right. = Yer completely right 

Your brother will be fine. = Yer brother will be fine 

Is this book yours? = Is this book yers
  

To is pronounced TA after voiceless sounds and  

DA after voiced sounds