as in teacher / /
is pronounced in UK English when followed by a vowel sound
and not when followed by a consonant sound. In US English,
it is always pronounced.
primary
stress (the part of the word you emphasize most), as in above.
secondary
stress (the part of the word you emphasize as well as, but not
quite as much as, the primary stress), as in backyard.
/
can be pronounced or not. 
/
is pronounced in UK English when followed by a vowel sound
and not when followed by a consonant sound. In US English,
it is always pronounced.
.
.