Sentence stress is the combination of strong words and weak words in a sentence, which creates a sort of rhythm. Strong words, such as nouns and verbs, are spoken stronger and more clearly than weak words, such as articles, pronouns or prepositions. (See Sentence Stress Part 2)
Weak words are not usually pronounced very clearly because they are spoken quickly, and they get reduced. This means that part of their sound is missing. Reducing weak words makes it easier to say them quickly.
Here are some examples of weak words that are used every day, and are normally reduced.
Prepositions: to / for / at / then / from / on / with.
Pronouns: you / your / he / she / it / them / his / him / her.
Helping verbs and BE: can / do / have / am / are / is / been / will.
Others words: and / an / the / or / than.
Notice, however, that when I say these words as part of a list, I do not say them with reductions. The reductions happen when they are in a sentence.
The most common ways that weak words get reduced are the following.
The most basic kind of reduction is using a schwa sound instead of a clearly pronounced vowel. In these examples, the word in parentheses after the sentence is the word that has a schwa rather than a full vowel sound.
I love to read. (to)
Look at this! (at)
They took it already. (it)
Do you like it? (do/you)
What is that? (is)
We need more than that. (than)
Sometimes a vowel is reduced so much, that it gets skipped completely. This is how some contractions are formed. In these sentences, the vowel of the weak word is missing.
He has to go. (to)
Thanks for your help. (for/your)
I’m almost finished. (am)
It’s getting late. (is)
We’re not ready yet. (are)
Another very common kind of reduction is skipping the “H” in these words: have / has / had / he / her / him / his. In these sentences, those words are weak and the “H” is missing.
They will call him later.
We should have waited.
Can her brother drive?
I had hoped to finish sooner.
It is important to know that H-deletion is only for weak words. If one of these words is said with strong stress, the “H” does not get deleted. For example, if I say: “That’s his book not mine” the “H” in the word “his” is said clearly because the word is strong. Also, when the word “have” is a main verb, it does not get reduced, as in “We have two days left.”
Other skipped consonants
Besides “H”, there are a few other consonant sounds that regularly get skipped.
“F” in the word “of”: We have lots of time.
“V” in “have”: He should have told us.
“D” in “and”: Let’s stop and eat.
“W” in “will”: That’ll be fine.
Sentence Stress Part 5 shows how some frequently used weak words can be confused with each other, because they can sometimes sound the same!