Modeling is an integral part of of the software developement process because it allaws a better understanding of its structure and function.
A modeling language is any graphical or textual computer language that provisions the design and construction of structures and models following a systematic set of rules and frameworks.
They are basically pseudo-languages that developers like to use to better represent the ideas of the software they are trying to build. The modeling languages can be of two types which are:
- Graphical modeling
In this type of languages we use diagrams which make use of symbols to represent concepts and lines to represent relationships between these concepts.
This is an example of a modeling language, each symbol represents something according to its shape and the lines have different relationships that you make explicit through text, this way you represent your system graphically which is easier to visualize than just thinking the abstract model in our heads.
- Textual Modeling
Textual modeling languages use keywords with parameters or other common terms to make something like pseudo-code.
You make constructs with text base only instead of using shapes like the graphicla ones. This ones can be harder to read but closer to the reality that you want.
References:
https://www.techopedia.com/definition/20810/modeling-language
Computer Systems Engineering 