I can't exactly hear the sound of 'd in cassettes, like: She'd make it. She'd be with them very soon.
I tried to listen them in youtube. I found I could hear it when some native english speakers speak slowly and clearly. (https://www.youtube.com/watch?v=MzhjD-XrYjg) But in another video (https://www.youtube.com/watch?v=JSSM8mBq3TI), the sound of 'd doesn't seem to be pronounced. (Is it right?)
I want to ask if native english speakers pronounce and hear the sound of 'd in conversation?
Thanks.
You're right, most speakers don't pronounce this d clearly. It's often dropped entirely.
When I say I'd drop it it sounds exactly like I drop it unless I'm making an effort to enunciate. Likewise I'd just go is indistinguishable from I just go. I think this is typical.
The d is clearest when it's followed by a vowel. When I say I'd ask, my tongue briefly touches the roof of the mouth. You can hear it slightly interrupt the flow of air. When I say I ask there is no obstruction of air at all, and the I sound blends seamlessly with the short a sound.
Short Answer
Native English speakers hear the “d” that occurs in would, had, and did contractions insofar as the stages of its articulation are audible. The audibility of its stages of articulation depends on its phonemic environment, the rate of speed at which it’s produced, and the level of formality the speaker means to convey. There are many instances of occurrence when the 'd' is not pronounced or is pronounced differently and is therefore not heard.
Thousands of videos of examples of I’d, you’d, he’d, she’d, it’d, we’d, they’d, that’d, there’d, what’d, where’d, when’d, who’d, why’d, how’d, etc. can be found at https://youglish.com/.
For video examples of MRI pronunciations, visit the following sites. https://sail.usc.edu/span/rtmri_ipa/index.html
Full Answer
The production of the phoneme /d/ in its “ideal” or standard form in English—for instance, when pronounced in isolation—can be divided into three stages. (The stages below are paraphrased from Applied Phonetics: The Sounds of American English by Edwards and Introducing Phonetics and Phonology by Davenport and Hannahs.)
First, the front of the tongue is raised to come into contact with the alveolar ridge. This is called the closing stage.
Second, breath pressure builds up behind the tongue and alveolar ridge. This is called the closure stage.
Third, the contact between the tongue and alveolar ridge is broken as the breath and sound are released. This is called the release stage.
(Much of what follows is either paraphrased or taken directly from the sources cited above, tailored to address the OP’s inquiry and to meet the conditions of the investor’s bounty. Where I could not find a direct reference in the source texts, my conclusions are based on personal observation of my own speech. [I am a native speaker of General American English.] I’ve marked such instances with an asterisk.)
“In connected speech, each sound is, to some extent, shaped by the sounds that occur before and after it, so that every phoneme produced in speech is a variant form of an idealized or perceptually categorized speech sound.” – Edwards, p. 58. “When oral stops [such as [d]] are produced in ordinary connected speech, the [third stage, or] release stage may be missing, due to the influence of neighbouring sounds.” – Davenport and Hannahs, p. 21
The /d/ that occurs in the contractions (also known as auxiliary reductions) I’d, you’d, he’d, she’d, it’d, we’d, they’d, that’d, there’d, what’d, where’d, when’d, who’d, why’d, how’d, etc. is called the clitic form of the auxiliaries would, had, and did. This /d/ is realized in connected speech by several varied pronunciations, or allophones, depending on its phonemic environment (I’ve marked each variation as audible, less audible, inaudible, and/or no audible release):
Before [h], manner and place of articulation of this /d/ is standard (standard for English, that is) in careful, highly articulated speech: ‘I’d hide’ = [aɪdhaɪd̚] However, it is often wholly or partly devoiced. In hurried or casual speech, a very brief or very weak contact between the tip of the tongue and the alveolar ridge may result in the /d/ being pronounced more as an alveolar tap or flap.* [Audible/less audible]
Before [w], pronunciation is standard: ‘I’d wait’ = [aɪdwet̚] In hurried or casual speech, a very brief or very weak contact between the tip of the tongue and the alveolar ridge may result in the /d/ being pronounced more as an alveolar tap or flap.* [Audible]
Before [f] and [v], pronunciation is standard, albeit devoiced or only briefly voiced before [f]: ‘I’d find’ = [aɪdfaɪnd], ‘I’d vote’ = [aɪdvot̚]. In hurried or casual speech, a very brief or very weak contact between the tip of the tongue and the alveolar ridge may result in the /d/ being pronounced more as an alveolar tap or flap.* [Audible]
Before vowels, the clitic /d/ is flapped: ‘I’d agree’ = [aɪɾǝgɹi]. [Audible] “As well as being influenced by surrounding consonants, the alveolar stops also show variation between vowels in a number of varieties of English, though here the assimilation involves manner rather than place of articulation. A well-known instance of this is the phenomenon of ‘flapping’ found in many North American and Northern Irish accents of English, . . . the [d] being replaced by a sound involving voicing and a very brief contact between tongue tip and alveolar ridge. This sound is known as a voiced alveolar flap and is transcribed as [ɾ].” (Davenport and Hannahs, p. 26. Note: CGEL (p. 1616) states, “The clitic /d/ occurs only after vowels.” This convention often leads to the contractions it’d, that’d, and what’d being pronounced as id, thad, and wud: ‘It’d be fine’ = [ɪd̚bi faɪn̚], ‘That’d be great’ = [ðæd̚bi gɹet̚], ‘What’d you think’ = [wʌʤju θiŋk]. When’d, which is rarer than the other contractions, and whose “d” occurs only as the clitic form of “did,” occurs mostly before “you” and is therefore subject to palatalization: When’d you get here? = [wɛnʤju gɛʔt‿hiɹ].*
Before [d], a lengthening occurs. It could be thought of as there being no release stage of the first /d/, and there being no closing stage of the second /d/.* Instead, there is a lengthening of the second stage, the closure stage, of the first /d/: ‘I’d die’ = [aɪd̚‿daɪ]. This is sometimes called gemination. [No audible release]
Before [t], [s], and [z]: When there exists a sequence of homorganic consonants, that is, consonants with the same place of articulation, such as those in ‘I’d tell,’ ‘I’d sell,’ and ‘I’d zoom,’ the first consonant, the /d/, lacks a release stage, according to Davenport and Hannahs. “Rather than lowering then raising the [tongue], it simply remains in contact with the [alveolar ridge] during the production of both stops.” – Davenport and Hannahs, p. 21. While in this environment the /d/ might lack a release stage in a technical sense, I do think it’s beneficial to acknowledge that the breath pressure built up behind the tongue and alveolar ridge is eventually released; the release simply co-occurs with the release or air flow of the second consonant.*
Before [t], the release of the /d/ happens at the same time and in the same place of articulation as the release of the [t] and is unvoiced: I’d take = [aɪd̚‿tʰek]. [No audible release]
Before [s], and [z], the release of the /d/, which is devoiced before [s], happens at the same time and in the same place of articulation as “the body of the tongue is bunched and shifted slightly forward to be flattened toward the hard palate and grooved along its midline; the tongue making contact with the upper gum ridge laterally; the air flow being channeled through the groove in the tongue against the upper alveolar ridge and front teeth, creating turbulence (Edwards, pp.126 and 132).”: I’d sell = [aɪt̚sɛl], I’d zoom = [aɪd̚zum]. [No audible release]
The release stage may also be inaudible in non-homorganic clusters (i.e. a sequence of sounds which are produced at different places of articulation) due to a similar phenomenon, sometimes called linking. “When a word that ends with a stop consonant is followed by a word that begins with a consonant, the stop consonant is usually not released. [See my note above about acknowledging eventual release.] That is, the tongue or lips will move to the place of articulation of the stop consonant and then move immediately to the place of articulation for the next consonant.” – Teaching American English Pronunciation by Peter Avery and Susan Ehrlich, p. 85.
Before [ʧ] and [ʤ], the release of the /d/, which is devoiced before [ʧ], happens at the same time and in the same place of articulation as the release of the second consonant, the tongue moving slightly forward, flattening along the palate, and forming the channel through which the air flows upon release of the [ʧ], and [ʤ]: ‘I’d check’ = [aɪt̚‿ʧɛk], ‘I’d judge’ = [aɪd̚‿ʤʌʤ]. [No audible release/Inaudible]
Before [ʃ], and [ʒ], the release of the /d/, which is devoiced before [ʃ], happens at the same time and in the same place of articulation as “the tip of the tongue is lowered towards front teeth, and the front is raised toward the hard palate and is flattened slightly with a wide groove along the midline; the tongue contacting the upper teeth laterally; the air flowing through the oral cavity; turbulence resulting as it passes against the palate, gum ridge, and teeth (Edwards, pp. 137, 138, and 143)”: ‘I’d shake’ = [aɪt̚‿ʃek], ‘I’d zhuzh’ = [aɪd̚‿ʒʊʒ]. [No audible release]
Before [ɹ], while pronunciation is sometimes standard in careful or highly articulated speech, the release of the /d/ happens at the same time as the lips are rounded, the front of the tongue is lowered and retracted, and the back of the tongue is raised slightly for the [ɹ], resulting in a less audible or inaudible release: I’d read it = [aɪd̚ɹiɾɪt̚]. [Audible/Less audible/No audible release] In hurried or casual speech, a very brief or very weak contact between the tip of the tongue and the alveolar ridge may result in the /d/ being pronounced more as an alveolar tap or flap.* [Audible] Some speakers, due to the retraction of the tongue, will affricate this sequence: ‘I would read it’ contracted to ‘I’d read it’ = [aɪʤɹiɾɪt̚].
Before [j], the release of the /d/ happens at the same time as the tongue moving to a high front position and is slightly flattening toward the hard palate for the [j] articulation (Edwards, p. 188): ‘I’d use’ = [aɪd̚juz], ‘I’d yield’ = [aɪd̚jild]. In many instances, when /d/ occurs before /j/, “the two segments combine to form the palato-alveolar affricate” [ʤ]: ‘How’d you do that’ = [haʊʤju du ðæt̚]; ‘What’d you do’ = [wʌʤju du]. (Davenport and Hannahs, p. 35) This process is referred to as palatalization, affrication, or yod coalescence. Palatalization is a type of assimilation.
The following are more instances of assimilation. “In each case, the closure [and subsequent release of air] for the . . . ‘d’ will not be alveolar but will be at the place of articulation of the following segment.” – Davenport and Hannahs, p. 25.
Preceding the bilabials [p], [b], and [m], the closure and release for the “d” is also bilabial: ‘I’d play’ = [aɪb̚‿ple], ‘She’d be’ = [ʃib̚‿bi] (geminate lengthening applies), She’d make = [ʃib̚‿mek]. [Inaudible] In observing my own articulation of the above sequences, I found the following statement found in the “No Audible Release” Wikipedia article to be relevant: “. . . 'hundred pounds' may sound like [ˈhʌndɹɨb ˈpʰaundz] but X-ray and electropalatographic studies demonstrate that since inaudible and possibly weakened contacts may still be made, the second /d/ in hundred pounds does not entirely assimilate a labial place of articulation but co-occurs with it.”
Preceding the velars [k] and [g], the closure and release for the “d” is also velar: ‘I’d kill’ = [aɪg̚‿kɪl], ‘I’d go’ = [aɪg̚‿go]. [Inaudible] See note above regarding inaudible and weakened contacts co-occurring.
Preceding the dentals [θ] and [ð], the closure and release for the “d” is also dental: ‘I’d think’ = [aɪd̪‿θiŋk], ‘I’d then’ = [aɪd̪‿ðɛn]. [Inaudible]
Here are a couple of past posts that touched upon assimilation:
'Broagcast' - the /d/ sound in English
Why do people often say 'hambag' for 'handbag'?
Before [n], the release of the /d/ occurs when the velum is lowered for the nasal, allowing the air to escape through the nose: I’d know [aɪdⁿ‿no]. [Less audible/No audible release] This is called a nasal release.
Before [l], the release of the /d/ occurs when “the centre of the tongue tip remains in contact with the alveolar ridge for the [l], and the built-up air is released when the sides of the tongue lower (Davenport and Hannahs, p. 26)”: ‘I’d like’ = [aɪdˡ‿laɪk]. [Audible] This is called a lateral release.
