Liniking or Liasion two words 

We strongly recommend to read and practice these rules click here  or quran.pdf

The sukoon sign does not only link two letters but it frequently links two or more word ina sentence. Remember that the Tanween (lesson 8) and Tashdid signs (lesson 21)
both contain a letter with sukoon .  sukoon, Tanween and Tashdid join (liaison) two or more words in a verse thus slightly alter the pronunciation.
To read more about linking or liaison please practice Lesson 21 - 30

 IDGHAAM (Assimilation) (Idghaam Mithlayn)
 IdghaamMutaqaaribany
 (Idghaam Mutajaanisayn)