Louisa Fitzhardinge judges prospective Tinder dates on their grammar. She also sings, acts, tells jokes and has compulsory high-school language studies to thank for her involvement in this year’s Fringe Festival.

After falling in love with the rigidity of German, Fitzhardinge studied languages at university, which was where she discovered theatre. Since then she has worked as a voice-over artist, toured internationally with improvised-comedy troupes and has appeared in hit musicals around Australia.

“My life is a constant struggle, trying to coordinate my love of languages and theatre,” says Fitzhardinge.

One way the self-confessed nerd has combined both passions is Comma Sutra, a one-hour comedy cabaret featuring sexy songs about grammar, a German rap, hilarious puns and a quadrilingual finale.

Fitzhardinge’s latest fascination is AUSLAN (Australian Sign Language), a language she started learning after watching sign-language interpreters at theatre performances. The performance element of AUSLAN has been particularly rewarding and is a big part of her show.

“Do you know the sign for coconut?” she asks. “You pretend to shake a coconut above each shoulder like you’re doing a little hula dance.”

Fitzhardinge’s exuberance is contagious. Speaking to her feels less like an interview and more of a mutual appreciation for the English language as we joke about the grammatical errors we find frustrating.

“If someone messages me on Tinder and uses the letter ‘u’ instead of spelling it ‘Y-O-U’, they’re immediately out because I know we won’t get along.”

The actor once skipped lunch because a cafe emphasised the “freshest” in its ‘freshest’ soup sign. (She’s still wondering if the soup was fresh). She also recalls reading a sign proclaiming “The early bird get’s the worm!” The ill-situated apostrophe left Fitzhardinge so agitated she sent a letter urging the offenders – a well-known corporation – to correct the mistake.

“Some people use the word ‘literally’ when they mean ‘figuratively’, like saying a new TV show ‘literally’ blew them away,” she says. “I know it didn’t.”

Awkward mistakes when learning new languages are another source of inspiration, like that time Fitzhardinge described her holiday on a “boat” but actually signed the word “vagina”. Even having said – or signed – that, Fitzhardinge won’t be deterred from adding new languages to her repertoire. Including Dothraki from Game of Thrones.

“I might be just nerdy enough to learn,” she says laughing.

Originally a 10-minute performance for a university assignment, Comma Sutra grew into a sell-out, one-hour show at last year’s Melbourne Cabaret festival.

As well as receiving five-star reviews, the show inspired an ABC article and Facebook discussion that outed secret “grammar Nazis” everywhere.

“The good feedback has made me feel special and also vindicated from the people who say I’m too picky about grammar,” says Fitzhardinge. “I think there are many people out there who really love grammar and language who need a show like this. I’m glad to bring them out of the woodwork.”

Comma Sutra is playing on January 31 to February 4 at ACE’s Cabaret at Downstairs at The Maj, 825 Hay Street, Perth. Tickets start from $36 and are available here