* Hawaiian: His native language and the official language of the Kingdom.
* English: He was fluent in English, having received an education at the Royal School in Honolulu and later traveled extensively in Europe and the United States.
* French: He was known to have spoken French, although the extent of his fluency is unclear.
It's possible he may have also had some knowledge of other languages, given his extensive travels and diplomatic engagements, but these three are the ones most commonly documented.