Here's why and some terms you can use:
* Bilingual means speaking two languages fluently.
* Trilingual means speaking three languages fluently.
* Multilingual is a general term for people who speak more than two languages.
You could use these terms together:
* Bilingual and trilingual
* Multilingual, speaking two and three languages
You could also use more descriptive language:
* Someone who speaks two languages fluently and three languages with proficiency
* A person fluent in two languages and proficient in a third
Ultimately, the best way to describe someone's language skills depends on the context and the specific information you want to convey.