Strong & Weak Forms

In connected speech, many of the ‘small’ words we use very frequently tend to take on a different ‘shape’ from the one listed in the dictionary. All of these words belong to the category of function words, i.e. they are words that have little semantic content of their own, but tend to have more grammatical or referential function in relating content words or higher syntactic units to one another. Function words are essentially closed class words, such as pronouns, prepositions, conjunctions, auxiliaries, etc. Below, you’ll find a table listing these words, together with their strong or dictionary form, as well as their potential weak forms. The following tables are based on Roach, 2000, with slight modifications/additions.
In general, weak forms do tend not to occur in sentence-final position or in contrastive/emphatic use.

Determiners/Quantifiers

orthography	strong form(s)	weak form(s)
the	ði:	ðɪ, ðə
a/an	eɪ, an	ə, ən
some	sʌm	səm, sm̩

Pronouns

orthography	strong form(s)	weak form(s)
his	hɪz	ɪz
him	hɪm	ɪm
her	hɜ:	ə
you	ju:	jʊ, jə
your	jo:	jə
she	ʃi:	ʃɪ
he	hi:	ɪ
we	wi:	wɪ
them	ðɛm	ðəm, əm
us	ʌs	əs, s

Prepositions/‘Particles’

orthography	strong form(s)	weak form(s)
than	ðan	ðən
at	at	ət
for	fo:	fə
from	fɹɒm	fɹəm, fəm, fm̩
of	ɒv	əv, v
to	tu:	tə, tʊ
as	az	əz, z
there	ðɛə	ðə

Conjunctions

orthography	strong form(s)	weak form(s)
and	and	ənd, ən, n̩d, n̩
but	bʌt	bət
that	ðat	ðət

Auxiliaries

orthography	strong form(s)	weak form(s)
can	kan	kən, kn̩
could	kʊd	kəd
have	hav	əv, v
has	haz	əz, z
had	had	əd, d
will	wɪl	l
shall	ʃal	ʃəl, ʃl, l
should	ʃʊd	ʃəd
must	mʌst	məs, məst
do	du:	də, d
does	dʌz	dəz, z
am	am	əm, m̩
are	ɑ:	ə
was	wɒz	wəz
were	wɜ:	wə