With the English sibilant 's' (voiceless alveolar sibilant) could the tip of the tongue be touching the back of the upper teeth?

Question

The wikipedia's Voiceless alveolar sibilants section states:

The voiceless alveolar sibilant is a common consonant sound in vocal languages. It is the sound in English words such as sea and pass, and is represented in the International Phonetic Alphabet with ⟨s⟩. It has a characteristic high-pitched, highly perceptible hissing sound. For this reason, it is often used to get someone's attention, using a call often written as sssst! or psssst!.

However is the English sibilant 's' truly alveolar for everyone or does it have some dental/post-dental quality to it for some native speakers? What I mean is whether the tongue tip is not supposed to touch the back of the upper teeth

As Alveolar consonant states:

Alveolar consonants (/ælˈviːələr, ˌælviˈoʊlər/) are articulated with the tongue against or close to the superior alveolar ridge, which is called that because it contains the alveoli (the sockets) of the superior teeth. Alveolar consonants may be articulated with the tip of the tongue (the apical consonants), as in English, or with the flat of the tongue just above the tip (the "blade" of the tongue; called laminal consonants), as in French and Spanish. The laminal alveolar articulation is often mistakenly called dental, because the tip of the tongue can be seen near to or touching the teeth. However, it is the rearmost point of contact that defines the place of articulation;

So as per the above, could the tip of the tongue be touching the back of the upper teeth for the English 's'? That is, does its characterization as an alevolar sibilant prohibit the tip of the tongue from touching the back of the upper teeth during its articulation?

Answer 1

To form an [s], the tongue creates a furrow along its midsagittal line (that line that runs down its middle) while the sides of the top of the blade/tip of the tongue make light contact with the alveolar ridge. Meanwhile the velum—that flap of skin with a punch-ball hanging off it at the back of your mouth— raises to prevent the air coming up from the lungs from leaving through the nasal cavity. This air, instead, gets forced at high pressure through the mouth and whistles through the tunnel created by the furrow and the alveolar ridge. The large volume of air at high pressure and the tiny aperture creates a turbulent jet-like stream which hits the back of the top teeth before exiting the mouth. This is heard as noisy, voiceless, sibilant friction.

When the OP asks whether the tip of the tongue may be in contact with the back of the top teeth, the answer is that if the groove along the tongue is maintained so that the air still escapes through a central channel then, yes, although the sibilant will have a slightly lispy quality. However, the apex of the tongue, in other words the tip of the tip of the tongue, may not touch the back teeth. This would prevent the air from leaving the oral cavity altogether (try it at home!). Some speakers may use something approximating a dental fricative, [θ], to represent English /s/, but then this would not be an [s]!

Answer 2

Some individuals do have non-canonical [s], see this dentist's ad which talks about treatment. I assume you mean "postalveolar", since "postdental" but not postalveolar is, indeed, "alveolar". Again, some people have postalveolar s. Sometimes people say "Smith has a lisp" (we have a name for it) or "Smith talks funny", or maybe we don't notice. Given the billion speakers of myriad dialects, anything is possible. A more interesting question is whether there are dialects that systematically use a dental or post-alveolar pronunciation.

Answer 3

I am not sure if your question is primarily about whether there is contact or not or whether the area of contact is alveolar or dental. I will try to address both issues.

That is, does its characterization as an alevolar sibilant prohibit the tip of the tongue from touching the back of the upper teeth during its articulation?

I do not know what phoneticians define as "touching the teeth." I have a reasonably standard pronunciation of American English; and I could say that, technically speaking, my teeth do not actually touch the center of the alveolar ridge, but it does touch at the sides. It doesn't actually touch in the center in order to be able to produce the sibilant component of the sound.

I have always assumed that "touching" in phonetic descriptions is not meant to be taken literally when describing sibilant and fricative consonants, since actual touching would imply that the movement of air is blocked (resulting in a stop consonant); however, the position is so close to the alveoli that calling it "touching" does not surprise or offend me either. In my feeling, calling it "touching" is closer to what I feel the position is than calling it "not touching" or calling it an approximant.

So as per the above, could the tip of the tongue be touching the back of the upper teeth for the English 's'? That is, does its characterization as an alevolar sibilant prohibit the tip of the tongue from touching the back of the upper teeth during its articulation?

That is correct. Calling it alveolar is correct and is inconsistent with contact with the upper teeth. When I speak English, I use the former articulation. When I speak French, I use a slightly different articulation, which Wikipedia describes as denti-alveolar.

One think that maybe be confusing you and still occasionally confuses me is that simple descriptions of these sounds usually just specify the point of contact in the mouth; however, often the point of contact on the tongue is important (i.e., "laminal" or "tip"). The tongue can also have a relevant shape (e.g., retroflex). Even these descriptors have varying levels of detail so that for instance, "tip of the tongue," for European languages at least, seems usually to refer to an area slightly behind the tip, rather that to the tip itself.