The previous few lessons explained the different lengthenings caused by hamzah.  These lessons are now located in the tidbit archives. 
This lesson starts a new subsection in the lengthenings, that of a lengthening caused by a sukoon.  Two types of lengthenings caused by a presented (or temporary) sukoon will be explained in this lesson.  The next type of lengthening caused by permanent or fixed sukoon will be explained insha’ Allah over several future lessons.   

The Lengthening with a Presented Sukoon

Its definition: This medd occurs when there is only one letter after one of the three medd letters, it is the last letter of the word, this last letter has any vowel on it, and we are stopping on the last letter with a presented sukoon.
Just a reminder: The three medd letters are, the alif with a fat-h before it, the  saakinah with a kasrah before it, and the  saakinah with a dhammah before it.  It is called “presented sukoon” because the sukoon is presented on the letter when stopping on it, otherwise the letter is read with its vowel.  Note: If the last letter is a hamzah there are then two medd in one, and   .  This will be explained, insha’ Allah in the  or stronger of two causes section, soon.

 Its rule: It is permitted to lengthen this medd two, or four, or six counts when stopping on it.  When not stopping on it, the last letter is read with a vowel and the medd letter is lengthened two vowel counts, the normal measure for ,or natural lengthening. 

Examples:

Click here to listen to this medd with 2 counts

Click here to listen to this medd with 6 counts

The Soft Lengthening

Its Definition: It occurs when a “leen” letter 
( or  with a sukoon, preceded by a letter with a fathah) is followed by one letter only in the same word and we stop on the last letter in the word with a presented sukoon.
 Its rule:  It is allowed to lengthen this medd 2-4-or 6 vowel counts when stopping on the word. When continuing reading (not stopping on this word), there is a slight lengthening of the “leen” letter, referred by the scholars as  "" which is less than two vowel counts, but longer than one vowel count.

Examples:

Click here to listen to this aayah

The difference between and

The presented sukoon lengthening 
( ) is stronger than the .  If the weaker of the two () precedes the stronger () in a phrase, the stronger should then be the same length or longer in length than than the weaker. An example of this in the following aayah:

Al-Baqarah 2

When we stop at the word , we stop with the soft lengthening ().  This “leen” lengthening can be lengthened 2, 4, or 6 counts.  Three words later, if we stop on the last word of the aayah , we stop with a presented sukoon lengthening that must be equal to the selected length of the “leen” medd or stronger.  If for example we stop on the word with two vowel counts, we can stop on the word with our choice of 2, 4, or 6 counts, since all are equal to or greater than the two vowel counts we used for the “leen” lengthening.  If however, we stop on the “leen” lengthening on the word with four vowel counts, we can only stop on the word with the presented sukoon lengthening with either four or six vowel counts. 

When the stronger medd which is the presented sukoon lengthening
() precedes the weaker soft lengthening (), the weaker medd then must be equal or less in length than  the stronger one. An example of this is in the aayah:

Al-Anfaal 65

If we stop on the word there is a presented sukoon lengthening, since there is an alif before the last letter, and we put a presented sukoon on the last letter when stopping.  We can stop on the presented sukoon lengthening () with 2, 4, or 6 vowel counts.  A second place to stop in this aayah is on the word .  There is a  saakinah preceded by a fat-h making a “leen” letter and this is followed by only one letter.  When stopping on this word, we put a presented sukoon on the last letter of the word, in this case , and now have a soft lengthening ().  The “leen” lengthening must be equal or less than the presented sukoon lengthening.  If we stop on the word with four vowel counts, we can only stop on the word with two or four vowel counts.  If we stop on the word with two vowel counts, we can only stop on the word with two counts.  Lastly, if we choose to stop on the word with six vowel counts, we then can stop on the word with two, four, or six vowel counts, since all are equal or less to the six vowel counts we used for the presented sukoon lengthening on the word .