In the phonology of stress-timed languages, the weak form of a word is a form that may be used when the word has no stress, and which is phonemically distinct from the strong form, used when the word is stressed. The strong form serves as the citation form. A weak form is a word as an unstressed syllable, and is therefore distinct from a clitic form, which is a word fused with an adjacent word, as in Italian mangiarla, 'to-eat-it'. A word may have multiple weak forms, or none. In some contexts, the strong form may be used even where the word is unstressed.

In English, most words will have at least one stressed syllable, and hence no separate strong and weak forms. All words which do have distinct strong and weak forms are monosyllables, and are usually function words or discourse particles. For most of these, the weak form is the one usually encountered in speech. As the extreme example, the strong form of the indefinite article a is used only in the rare cases when the word is stressed: naming the word, or when emphasizing indefiniteness. For instance:

Question: "Did you find the cat?"

Answer: "I found a [eɪ] cat." (i.e. maybe not the one you were referring to).

Otherwise (unless one is risking pomposity) the weak form [ə] is used for a.

The main words with weak forms in Received Pronunciation are:

Other dialects or accents may have others. Many varieties have a weak form [jɚ] for your, which can, for example in dialogue, be spelled "yer". In some British regional pronunciations, such as Hiberno-English, there is a weak form [mi] for my, often spelled "me". A greater difference between strong and weak forms, and a more widespread use of weak forms, are associated with less formal registers, and may be indicated in writing by eye dialect spellings, such as ’em for them [əm]. The most formal register in this sense is singing, where strong forms may be used almost exclusively, apart (normally) from a.

In deriving weak forms from strong forms, the vowel is usually more central and may be shortened, sometimes merging to a syllabic consonant with any following [l], [m] or [n]. Changes to consonants are less frequent: an initial h is dropped unless the word is at the start of an utterance, and dental consonants may be elided at the end of the word. For example:

• The word and has strong form [ænd] and weak forms [ənd], [ən], [nd], [n].
• The word to has strong form [tuː], weak form [tʊ] before vowels, and weak form [tə] before consonants (or even before a vowel, inserting a glottal stop in between).

The 'em form of them is derived from the otherwise obsolete synonym hem: an unusual form of suppletion.

Some weak forms have restricted usage. For example, in RP usage:

• Dropping the [h] of her is common in "I saw her yesterday" but not in "I saw her mother" (possessive her).
• Demonstrative that uses the strong form even when unstressed. "I like that colour" (demonstrative, strong), as against "I like that you like it" (conjunction, weak).
• Stranded auxiliaries and prepositions use the strong form. "I found what I'm looking for." (stranded for, strong) as against "I'm looking for money" (for before noun, weak).

Differences between General American and Received Pronunciation

Differences in pronunciation between American English (AmE) and British English (BrE) can be divided into:

• differences in accent (i.e. phoneme inventory and realisation). Accents vary widely within AmE and within BrE, so the features considered here are mainly differences between General American (GAm) and British Received Pronunciation (RP); for information about these accents see this article.
• differences in the pronunciation of individual words in the lexicon (i.e. phoneme distribution). In this article, transcriptions use RP to represent BrE and GAm and to represent AmE.

In the following discussion

• superscript after a word indicates the BrE pronunciation of the word is a common variant in AmE
• superscript after a word indicates the AmE pronunciation of the word is a common variant in BrE

Problems with lexical stress

It is sometimes difficult to decide how to mark word stress in a dictionary. A dictionary should ideally show lexical stress, i.e. the stress pattern that the word has when spoken in isolation with no special pragmatic factors in play (no special contrastive stress, for example). You can usually check this by making the word a one-word utterance, as an answer to a question such as What’s that?, What’s it like?, What did he do?, How did he do it?.

There’s a particular difficulty with compound adjectives such as God-given, hard-drinking, long-term, saber-toothed. Lexically it is probably correct to show them all with double stress (end-stress), so ˌGod-ˈgiven, ˌhard-ˈdrinking, ˌlong-ˈterm, ˌsaber-ˈtoothed.

The trouble is that all double-stressed words are candidates for stress shift. And adjectives like these are usually attributive: they precede a noun, itself likely to be stressed, so that in practice they undergo stress shift much more often than not.

our 'God-given 'rights
a 'hard-drinking 'sailor
'long-term 'plans
a 'saber-toothed 'tiger

It may feel slightly awkward to force them into predicative position:

What sort of rights are these? — God-given.
What kind of sailor was he? — Oh, hard-drinking.
What plans did you make? — Long-term ones.
What kind of tiger was it? — Saber-toothed.

If we do this, however, I think it becomes clear that they are indeed double-stressed.

What sort of rights are these? — 'God-'given.
What kind of sailor was he? — 'Hard-'drinking.
What plans did you make? — 'Long-'term ones.
What kind of tiger was it? — 'Saber-Toothed.

If we answered the last question by saying

——'Saber-toothed.

then we would implicitly be contrasting saber- with some other kind of toothedness. But sometimes this kind of contrastiveness becomes fossilized, as in pear-shaped, so that initial stress is the only possibility.

It’s 'all gone 'pear-shaped.

There is also a problem in deciding whether to show words such as one-size-fits-all or MRSA with four stresses or (as they are usually pronounced) just with two; and likewise whether to show three or two lexical stresses in words such as nondenominational.