What's the deference between web programming language and mobile application programming language?

I am not sure that is your question is the right question to ask, many languages are used for both web and mobile, and some of these languages used to develop both web and mobile applications.

Also, most of the mobile applications rely on API behind it so the web is used to serve these applications.

They are not "programming" languages. They are markup languages.Their purpose is to define the elements of a web page (paragraphs, title, buttons, forms, etc) and the way they look (their color, font type, position on the page, size, etc).

• HTML is the markup language of the web. Its purpose is to define the content of the web page.
• CSS is the stylesheet of the web. Its purpose is to describe how the content should be displayed.
• Javascript is the client-side programming language of the web. Its purpose is to enable dynamic pages rendering  and logic inside the browser. It can also be used on the server-side.

Thanks for the invite. But my views and answer won't differ from

Mr Issa Mohammad Hassan Khalil

Mobile application development is the set of processes and procedures involved in writing software for small, wireless computing devices such as smartphones or tablets.

Web app development is the creation of application programs that reside on remote servers and are delivered to the user’s device over the Internet.

Mobile application development is the set of processes and procedures involved in writing software for small, wireless computing devices such as smartphones or tablets.More and more organizations looking to hire mobile app developers to hop on the cloud wagon are facing application and data integration roadblocks. Getting around them is difficult but possible—and a step-by-step approach can help.Mobile application development is similar to Web application development and has its roots in more traditional software development. One critical difference, however, is that mobile applications (apps) are often written specifically to take advantage of the unique features a particular mobile device offers. For instance, a gaming app might be written to take advantage of the iPhone's accelerometer.

Web app development is the creation of application programs that reside on remote servers and are delivered to the user’s device over the Internet.In this expert handbook, we explore the issues and trends in cloud development and provide tips on how developers can pick the right platform.Web apps are sometimes contrasted with native apps, which are applications that are developed specifically for a particular platform or device and installed on that device.

Web app development is identified with making sites, web application which utilizes different innovation like wordpress, PHP, ASP.net

While mobile app development allude to Mobile application advancement. Like iphone application advancement, Android application improvement and windows telephone advancement.

Web application development is the creation of application programs that reside on remote servers and are delivered to the user's device over the Internet. A web application (web app) does not need to be downloaded and is instead accessed through a network. ... Client refers to a computer application such as a webbrowser.

Mobile app development is a process by which a mobile app is developed for mobile devices, such as personal digital assistants, enterprise digital assistants or mobile phones. These applications can be pre-installed on phones during manufacturing platforms, or delivered as web applications using server-side or client-side processing