Emma searches for the right words to say to George in “The Language Archive.”

You can know every word in the dictionary and still not be able to express yourself. That’s the idea behind Julia Cho’s “The Language Archive,” now playing at the Round House Theatre. The play explores both the centrality of language to our emotions and its occasional inadequacies: Emma (Katie Atkinson) is so intent on expressing her love for George (Mitchell Hébert) that she learns Esperanto in an attempt to get closer to him and find the perfect words. Need to express your feelings? Here are a few invented languages you could try to learn.

Esperanto: Developed in the 19th century as a universal tongue with no irregular conjugations, Esperanto is perhaps the most well-known invented language. FUN FACT: Hungarian billionaire George Soros counts Esperanto as his first language.

Klingon: This language of “Star Trek” aliens was created by linguist Marc Okrand in the 1980s. Rather than just inventing a few words for the show, he developed a complex structure. FUN FACT: There is no term for “hello,” but you can substitute “nuqneH,” meaning “What do you want?”

Solresol: This language has only seven syllables: do, re, mi, fa, sol, la and ti. Jean-Francois Sudre based it on the musical scale, so you can sing words and sentences or play them on an instrument. FUN FACT: To find the opposite of a word, reverse the syllables. For example, “misol” means good and “solmi” means evil.

Round House Theatre, 8641 Colesville Road, Silver Spring; through March 10, $15-$25; 240-644-1100. (Silver Spring)