Short answers, pulled from the story.
Marc Okrand created the structured Klingon language for Star Trek III: The Search for Spock in 1984. He enlarged the lexicon based on James Doohan's original dozen words recorded for Star Trek: The Motion Picture in 1979.
Klingon uses retroflex and uvular consonants to sound alien to human ears and contains twenty-one consonants and five vowels. Case-sensitive letters denote sounds not native to American English, with uppercase letters representing sounds pronounced further back in the throat than normal English sounds.
Arika Okrent estimated there might be only 20 to 30 fluent speakers in her 2009 book. d'Armond Speers raised his son Alec to speak Klingon as a native language until he stopped responding after turning five years old.
At least nine works of world literature have been translated into Klingon including Hamlet titled qaplaH and The Epic of Gilgamesh becoming paqbatlh. The Bible has also been translated from English into Klingon through multiple projects coordinated by Melanie Roney.
Netflix provided Klingon subtitles for Star Trek: Discovery starting with its digital-only release in 2017. Lieven L. Litaer translated the entire first season using romanized transliteration.