TNG Season 5 Episode 2: Darmok

How do you talk to a race that appears to speak in gibberish, even with the universal translator doing its best? According to the Children Of Tamar, the best solution is to beam your Captain and that of the vessel you are trying to communicate with down to a planet with a dangerous creature, give each officer a knife and see if they can work out their differences. Paul Winfield (who also played Captain Terrell in Star Trek II: The Wrath Of Khan) does a superb job as the Tamarian Captain who communicates with Captain Picard by metaphor – it turns out that knowing the story of the example you’re citing helps quite a bit.
The late, great Michael Piller remarked of this episode “I just think Darmok is the prototype of what Star Trek should be.” It has also be used by Linguistic teachers as an example of how language can develop while the premise alone in the form of the billing blurb for the episode inspired Russell T. Davies to write Midnight, from the fourth season of Doctor Who‘s revival.

Plot

The Enterprise makes contact with a Tamarian ship in orbit around the planet El-Adrel. The Tamarians had been previously contacted by the Federation, but could not be understood — although the universal translator can translate their words, they communicate by using brief allusions to their history and mythology to convey thoughts and intentions. Likewise, the Tamarians cannot understand Captain Picard's straightforward use of language.
The Tamarian captain, Dathon, has himself and Picard transported to the planet's surface. The Tamarians then cast a scattering field that blocks further transporter use. Dathon utters the phrase "Darmok and Jalad at Tanagra" and tosses Picard a dagger. The next morning, Dathon comes running and Picard realizes there is a hostile predator in the area. Picard begins to understand the Tamarians' jargon when he recognizes one allegory as a tactic to fight the beast. The two attempt to battle the beast together, but the Enterprise's unsuccessful attempt to beam up Picard prevents him from participating at a crucial moment. Dathon is severely wounded.
On the Enterprise, First Officer Riker and the crew struggle to understand the aliens' language. They make several efforts to rescue the Captain, all foiled by the Tamarians. While tending to Dathon's wounds, Picard slowly deduces that Darmok and Jalad were warriors who met on the island of Tanagra and were forced to unite against a dangerous beast there, becoming friends in the process. Dathon tried to recreate this event with Picard, hoping to forge a friendship through shared adversity. Picard recounts for Dathon the Epic of Gilgamesh, a story that parallels the allegory of Darmok and Jalad. Dathon seems to understand the story but succumbs to his injuries.
The Enterprise fires on the Tamarian ship, disabling the scattering field, and beams up Picard. A battle begins, but just when mutual destruction seems certain, Picard enters the bridge and uses his newfound knowledge to communicate with the Tamarians. The Tamarians joyously perceive that Picard's eyes have been opened. Picard offers them Dathon's diary and dagger after telling them of their captain's sacrifice. The Tamarians tell him to keep the dagger in remembrance of Dathon, and record the incident as "Picard and Dathon at El-Adrel" — a new phrase in their language.
Picard later reads the Homeric Hymns, explaining to Riker that studying their own mythology may help them relate to the Tamarians. He mourns that Dathon sacrificed himself in the hope of communication, and wonders if he would have done the same.