I am confused about the place of Articulation of s and z betweenAr. And english

[alm-alr]

 I am confused about the place of Articulation of  s and z between Ar. And english
Hallo,
 A lot of english phonetics references as well as videos I have seen  like the one herewith (at   5:45 ) says that ,t,d,s,z  are articulated  as the tip of the tongue touchs the upper Alveolar ridge
https://www.youtube.com/watch?v=-e66ByetpDY
I  was  accepting this ( definetly s ,ans z ) all   the time without trying it myself , till I saw an Ar. video about the correct way of  pronouncing  Ar. consonants when reciting Quran ( this ia called Tajweed ) where they say that -t,and d -are articulated in the same way as english video says , but (s ,and  z ) are articulated with the tip of the tongue on the inner face of the lower teeth  not the upper  Alveolar ridge   as shown here
https://www.dropbox.com/s/mydbvm9gkz3dbbp/s-z-t-d - P.of Articulation.pdf?dl=0
Trying it myself I found it absolutely correct …. I am confused …. what about you  ??

[Daniel]

Sounds like Arabic has dental consonants rather than alveolar consonants. Different languages use different places of articulation, and a few actually contrast the two (as in some Australian languages and Dravidian languages).

[alm-alr]

are you sure about this ?? Besides Ar. I am also speaking English  very long time ago , but i never noticed that I pronounce the "s' and 'z"  with the tip of the tongue touching the inner surface of the lower teeth  not the upper  Alveolar ridge , till  the time i saw that Ar.video ..since then I tried to do it with the upper  Alveolar ridge , but I couldn't  !!!!!!!!
it's not possible to believe that  I was  all the time  pronouncing  another 's" or 'z'  than yours ??

[Daniel]

it's not possible to believe that  I was  all the time  pronouncing  another 's" or 'z'  than yours ??

You probably were. This difference is not very important or salient in perception.

Spanish, for example, has dental stops rather than alveolar stops. The distinction isn't very obvious (for a "Spanish" or "English" accent in the other language), if you ignore the other factors (like aspiration).

[alm-alr]

hi djr33
  I have already found a text in  "A course in Phonetics by P.Ladefoged and K.Johnson ,p.12 ch. 1 (sixth edition )" :
For example, some people  pronounce [ s ] with the tongue tip tucked behind the lower teeth, producing the constriction at the alveolar ridge with the blade of the tongue; others have the tongue tip up for [ s ]. Feel how you normally make the alveolar consonants in each of these words, and then try to make them
in the other way.....

This text shows that both you, and the Ar.lecturer in the video have not well recognized the 2 ways which people "irrespective of their language "  pronounce a consonant like 's'.

[Daniel]

That's what happens when a language does not have a contrast between those two kinds of sounds. (Note also that there are potentially bigger differences when they are meant to be contrastive such as tongue shape. Place of articulation isn't 100% of the shape of the constriction.) But in other languages (such as some Dravidian languages which contrast dental/alveolar/retroflex) that difference is important.