Why there are too many of programming languages ? C, C++, C#, Pascal, Delphi, Python, Visaul Basic, Basic, Cobol ... etc

There are too many languages out there for programming for computer. All of these were introduced on different occasions for different purposes of course. Although many of them are same in syntax. 

But at the end these all are converted to machine language (i.e Binary Language or Mostly known as Assembly language). So is result computer understand only one language.

generally programming languages are like spoken languages .. they have ways to express your self with. some ppl prefer to express their things in different ways. but not all languages can give you the same result . and most importantly not all languages work in all platforms

e.g Basic is very easy language to learn but of course it is not as powerfull as C++ or java

each language of these have different technique and syntax plus for different purposes, like a human languages "Arabic, English, French,...,etc" 

It is because of evolution in programming languages and application of these languages in different situations.Just like in cars there are models then new models of the same car come up. Different companies make different cars and all have some advantages and disadvantages in different conditions. You will not go to a race with a luxury car or drive a F1 in your neighborhood.Similarly, Every programming language have pros and cons in different situations.

Basm Allah Alrahman Alrahim 

I agree with you at one point and disagree with you with the second point , first point that all languages must be one language , some companies try to make that like Microsoft with dot net if you understand one of the package that mean almost that you understand all Visual studio , but they don't like Linux or any others operating systems so they don't made compiler for them , JAVA made compiler or JVM for all operating systems but they through out something called pointer , and JVM [ java virtual machine ] look like another level of compilers [ that mean codes changed through compiler to compiler then to machine]  the second point is that stupid machine , that stupid machine if we rebuild with the right way it may help our brain against making bad things ! , if you don't understand what I mean , remember way always people became bad persons ? , because they don't save what they learn and study what they made wrong and make restriction to those bad things [ that why god give us al quran to be saved all the time for all generation ] , so this machine if you use it for all generations with restrictions to your brain from doing bad things by make you remember good things or by force like three lows , that will lead us to be good of course Ensha Allah , any way be careful from that machine because all strong countries can't be strong without it . 

 Thank you for this question that help us to search and learn

The design of each language has a history behind it. Each language has its own strength and weakness(pros and cons). There is always an objective behind designing a language. 

This also explains that the focus is never on the language, but on the objective to solve a problem.

it is a historical thing, the languages evolved based on the different needs, as an example, C++ is an evolution for C, and C# is an evolution for C++, Java was created to support cross-platform development, and when the machines became more powerful the scripting languages became an equal competitor to the compiled languages. 

Hence comes the specific purpose languages like Fortran and COBOL.

Most of the languages are similar in the concept but may differ in the syntax and the supported libraries .