Words pronounced differently according to context

     [This is a fast-access FAQ excerpt.]
There is a general tendency in English whereby when a word with a
stressed final syllable is followed by another word without a pause,
the stress moves forward:  "kangaROO", but "KANGaroo court";
"afterNOON", but "AFTernoon nap"; "above BOARD", but "an aBOVEboard
deal".  This happens chiefly in noun phrases, but not exclusively so
("acquiESCE" versus "ACquiesce readily").  Consider also "Chinese"
and all numbers ending in "-teen".
   When "have to" means "must", the [v] in "have" becomes an [f].
Similarly, in "has to", [z] becomes [s].  When "used to" and
"supposed to" are used in their senses of "formerly" and "ought",
the "-sed" is pronounced /st/; when they're used in other senses,
it's /zd/.
   In many dialects, "the" is pronounced /D@/ before a consonant,
and /DI/ before a vowel sound.  Many foreigners learning English are
taught this rule explicitly.  Native English-speakers are also
taught this rule when we sing in choirs.  (We do it instinctively in
rapid speech; but in the slower pace of singing, it has to be
brought to our conscious attention.)
   Words that have different pronunciations for specialized
meanings include the noun "address" (often stressed on the first
syllable when denoting a location, but stressed on the second
syllable when denoting an oration) "contrary" (often stressed on the
second syllable when the meaning is "perverse"); the verb "discount"
(stressed on the first syllable when the meaning is "to reduce in
price", but on the second syllable when the meaning is "to
disbelieve"); the verb "process" (stressed on the second syllable
when the meaning is "to go in procession"); the noun "recess"
(stressed on the first syllable when it means "a break from
working", but on the second syllable when it means "a secluded
part"); the verb "relay" (stressed on the first syllable when it
means "to pass on radio or TV signals", but on the second syllable
when it means "to pass on something that was said"); and the verb
"second" (stressed on the first syllable when it means "to endorse
a motion", but on the second syllable when it means "to temporarily
re-assign an employee".  "Offence" and "defence", usually stressed
on the second syllable, are often in North America stressed on the
first syllable when the context is team sports.  (In the U.S., of
course, they are spelled with -se .)