Multi-language is when something is expressed in two or more languages. Multi-language is also referred to as multi-lingual. A person who has the ability to speak/ write/ express himself in more than two languages he is said to be multilingual.
So multi-lingual or multi-language refers to the expression of something in more than two languages. The fluency is also an important factor to be taken into consideration. The ability to express oneself in multiple languages with similar fluency is basically multi-language.
An example of something multi-language or multi-lingual is the United Nations general assembly where someone speaks in English, someone in French, someone in Spanish, someone in Chinese and someone in Hindi.
A lot of global companies ensure that their documents, exams, tests etc are in multiple languages as they have to interact with people, companies, organizations from across the world.
Apart from this, even softwares made by large enterprises give an option of selecting languages depending upon the preference of an individual. Even mobile phones, laptops etc have options for customers to choose from multi-language options.