One film was the clear favourite at the Oscars on Sunday night. The Power of the Dog had received no fewer than 12 nominations. But when the moment came for Liza Minnelli to read out the name of the Best Picture, the envelope Lady Gaga handed her contained a shock. The winner was...CODA, an independent film made for a modest $10m.

The letters stand for Child of Deaf Adults, and the film stars the British actress Emilia JonesThe daughter of Aled Jones, who as a boy sang Walking in the Air, the theme song from The Snowman. as Ruby Rossi, the only member of her family who can hear. As their link to the wider world, but also a talented singer, she faces a seemingly impossible choice between staying to help her parents run their fishing business or pursuing her own musical career.

Ruby's mother Jackie is played by Marlee Matlin, who became the first Deaf person to win an Oscar 35 years ago, when she took the Best Actress award for Children of a Lesser God. On Sunday Troy Kotsur, who plays Ruby's father Frank, became the second when he was named Best Supporting Actor.

In a speech made in sign language, he said, "This is our moment," dedicating his award to all Deaf and disabled people. He called the film's director Sian HederShe has directed only one other full-length film, the comedy drama Tallulah. "our bridge... you brought the deaf world and the hearing world together." He also named his father, who lost the ability to sign when he was paralysed in a car accident, as "my hero".

Around a third of the film's dialogue is in American Sign Language (ASLIt is based on 19th Century French sign language, and uses grammar which is more French than English.), with subtitles so that people who have not learnt it can follow what is being said. Matlin, the first person to be cast, insisted that all the other deaf roles should go to Deaf actors. In the French filmThe movie is a remake of La Famille Belier, which was the second most successful film in France in 2014. it was based on, the parents were both played by people who could hear.

Some critics and viewers, though, have reservations about how CODA presents the Deaf community. "The production's extensive use of ASL and its casting of deaf actors in deaf roles are milestones worth celebrating," writes John Hendrickson in The Atlantic. "But the Deaf performers play supporting roles, and we're principally following the journey of a hearing protagonist."

 "I would recommend CODA because it depicts deaf characters who seem, for the most part, authentic," says writer Sarah Katz, "with the caveatWarning. In Latin it means let him beware. that deaf people are not as needy as the movie portrays them to be".

Katz, like more than 90% of deaf or hard of hearing people, is the child of hearing parents. In an article for The New York Times, she describes the parents' dilemma: "Should they adapt themselves to their deaf child, learn sign language, and embrace deaf culture, or have their deaf child adapt to hearing culture, give her cochlear implantsTiny electrical devices which stimulate the nerve that allows us to hear.   or hearing aids, and train her in the precarious art of lip reading?"

But there is a case for learning sign language even if you do not need to. Research has shown that people who do are better are reading others' emotions, and at following directions. It has also been found that people who use extensive hand gestures make more of an impactGestures can even make you seem taller than you are. as public speakers.

Yes: It would enrich our spoken language as well as make it much easier to talk to deaf people. Signing makes us more creative, more imaginative and more empathetic. It also encourages us to look up from our phones and engage with people more.

No: It would make life unnecessarily complicated. Sign languages are difficult to master and could lead to confusion.

Or... We should learn cued speech, which uses a small number of hand gestures to make it easier for deaf people to lip read what others are saying. Invented in 1966, it can be picked up in just 48 hours.

A modest $10m - The Power of the Dog had a budget of $35.9m.

Emilia Jones - The daughter of Aled Jones, who as a boy sang Walking in the Air, the theme song from The Snowman.

Sian Heder - She has directed only one other full-length film, the comedy drama Tallulah.

ASL - It is based on 19th Century French sign language, and uses grammar which is more French than English.

French film - The movie is a remake of La Famille Belier, which was the second most successful film in France in 2014.

Caveat - Warning. In Latin it means let him beware.

Cochlear implants - Tiny electrical devices which stimulate the nerve that allows us to hear.  

More of an impact - Gestures can even make you seem taller than you are.