Bilingualism refers to the ability to speak two languages fluently. There are several synonyms that can be used in place of this term, such as multilingualism, polyglotism, and bi-lingual ability. Multilingualism is a term used to describe individuals or societies that have the ability to speak more than two languages fluently. Polyglotism refers to the ability to speak multiple languages, regardless of how many. Bi-lingual ability is a synonym that specifically refers to the capability to speak two languages with equal proficiency. All these words carry similar meanings and can be used interchangeably in different contexts.