Lojban is a constructed language that was designed to be as logical and unambiguous as possible. It is based on predicate logic, and its grammar is heavily influenced by that of Loglan. Lojban has been in development since 1987, and was originally created as a project to see if it was possible to create a language that was both logical and unambiguous.
Lojban is designed to be easy to learn for speakers of languages with Latin-based alphabets, and its grammar is relatively simple. However, the language does have a number of quirks that can take some getting used to. For instance, Lojban has no words for "yes" and "no", and instead relies on context to determine the meaning of a statement.
Lojban is still in development, and is not yet widely spoken. However, there is a small but dedicated community of speakers, and the language is slowly gaining traction. If you're interested in learning a constructed language that is both logical and unambiguous, Lojban may be the language for you.