There are many Languages in world today. some of the popular languages are : C++, Java, Ada, BASIC, PASCAL, COBOL, FORTRAN, SMALLTALK, VISUAL BASIC,.etc..
These all are high level languages, where as C is a middle level Language..

There are many reasons to learn C :
>> C is a neither a high level nor low level, it is a middle level language..
>> It is closer to hardware and number of the common programming languages
(ex: C++,Java,etc..) are based on C  and  Operating Systems(ex: Linux) is 
      developed using C.
>> C is a small language. because C has only 32 keywords and 20 of them are in
common use. Hence learning C is more easy when compared to any other 
      high level language.
>> Often it is said that C is the second best Programming Language for any
programming task.
>> C is a very old language that is since 1983, and hence number of the applications
are  available in C.