Question

There are many letters that are articulated from the tip of the tongue and I'm wondering where they are in relation to each other and which ones are closer to the teeth and furthest and so on. Could you please give me an idea about this?

Answer

The uses the sides of the tongue until they end at the tip, from a very slightly posterior position to the gum area used for the  and .  Imam Ibn Al-Jazaree in his prose about the principles of tajweed stated (translation): and the  from its tip, make it further down [from the ].  In Arabic, down in this case means closer to the teeth.  The  uses only the tip of the tongue, while the  uses the same gum area of the , but in addition to the tip also uses the top of the tongue.  The  therefore uses more area of the gum to accommodate the collision or separation of the tip and top of the tip during articulation. 

Closer to the teeth are the three letters .  They use the top of the tip of the tongue and the gum line of the two top incisors.  These three letters are those articulated closest to the teeth without actually using the teeth for articulation.

The whistle letters use the same tip of the tongue that the  uses, but the plates of the two top front teeth (close to the bottom edge) are used for the second area of articulation, not the gums.  Remember each letter uses two areas to articulate, and there is collision or separation (depending on the vowel) needed of these two areas to produce the correct sound of the letter. 

The last group of letters that use the tip of the tongue are: .  These letters use the top of the tip of the tongue, just as  do, but instead of the gum line, these letters use the bottom edge of the two top front teeth for their second point of articulation.