Characteristics
of Letters 
Part
7
Characteristics that have no opposites
This lesson starts the group of characteristics for certain letters that have no opposites, meaning when a letter or a group of letters has a characteristic of this type, there is no antithesis characteristic for the rest of the letters.
The Whistle 
Its linguistic definition: Sharpness of sound
Its applied tajweed meaning: It is the occurrence of an extra sound that is similar to the sound of a bird emitted from between the two lips (or teeth) when pronouncing a letter.
Its letters:
There are three letters that have this characteristic: 
,
,
and 
This sound is not a forced sound, but one that should come out naturally with the letters. Some may have difficulty producing this characteristic if they have a large over bite of the upper teeth. This can be overcome if the lower jaw is protruded so that the upper and lower teeth align. Another reason for the incorrect muting of this characteristic is if the tip of the tongue is pressed up with force on the plates of the teeth. If a small space remains between the tongue and the plates, the whistle can be emitting easily.
Imam Al-Jazaree said:
The Ease 
The linguistic definition: Easiness
Its applied tajweed definition: Emitting the letter from its
articulation point with ease without effort from the tongue.
Its letters: The 
and
the 
of
leen, meaning the
or
with
a sukoon preceded by a fat-h.
Imam Al-Jazaree said:
[and the “leen”, wow and ya’ with a sukoon and both have a fat-h before them]
The Deviation 
Its linguistic definition: Drifting
Its applied tajweed definition: Drifting of the sound of the letter as it leaves [its articulation point] due to the incomplete running caused by the tongue turning from its path.
Its letters :
and
The tip of the tongue sticks at the articulation point of the ,
(as in the characteristic of 
),
the sound then deviates off the sides of the tongue (as in the characteristic
of 
),
which is used also for the articulation point.
The sticks
at the left and right of the very tip to the second part of the articulation
point ie. the gums of the two front teeth (as in )
; the sound then needs to escape so that there will not be repetition or
trilling ( 
).
A small space at the very tip of the tongue is made so the sound can escape out
the mouth (as in )
and trilling of is
therefore avoided. The tip of tongue is somewhat cupped for this small space
to occur in the middle of the tip.
This is the reason both of these letters have the characteristic
of 
instead of or
.
Imam Al-Jazaree said:
[and the "deviation" is applied, in the laam and the ra']
Next lesson will, insha' Allah, continue with the characteristics that have no opposites.