Machine Language: Computers use binary system and all data or instructions ultimately have to be converted into the combination of 0s and 1s, so that the system can execute them. Each computer system generally has its own special machine language. For giving instructions, we need to have a standard format so that every programer can follow it. Machine language has a specific instruction set, in which instructions are specified.

    Since, machine language is directly based on the computer system characteristics, it does not require any additional software for translating instructions to what the computer can understand. Though this is a very efficient language, it is rarely used for writing programs because of the difficulty in executing it.

    Assembly Language: Assembly language was designed to facilitate writing programs compared to the machine language. In this, “mnemonic codes” are created, which the programer can directly utilize. For example, instead of using ‘0’ and ‘1’ to specify an operation, say “ADD”, programers can use “mnemonic code” “ADD” directly. Similarly, in assembly language, symbolic code for memory address of an operand can be used instead of specifying the address as “binary”. Today, assembly language is also used very often except by systems programers.

    High-level Language: Various high-level languages have been designed for helping in writing the program instructions. Some examples are BASIC, COBAL, FORTRAN, PASCAL, ALGOL, etc. High-level languages are English like languages with a predefined format. In these, the instructions are much more powerful compared to machine language or assembly languages. The most important feature of high-level languages is that they are machine independent and can be used on various computer systems.