Weak form and strong form

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.

English

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:

a, am, an, and, are, as, at, be, been, but, can, could, do, does, for, from, had, has, have, he, her, him, his, just, me, must, of, shall, she, should, some, than, that, the, them, there, to, us, was, we, were, who, would, you

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, replacing the 't' with a glottal stop or a flap).

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"^{[citation needed]} (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).