We're still trying to find the spaceship that Diana and Dimash traveled to Earth in lol.

You are asking a very common question about Diana's vocal range because as you know, the vocal range helps in defining a female singer's voice type.  At age 13 in 2017, her vocal range was measured from a low of D3 to a high of A5, and As of September 2021, at age 18, (she is now 19), during this performance her lower functional range was again measured and now her range is from a low of C3 to a high of B♭5.  But, it's not just how low she can go, it's the exceptional quality of her tone and timbre in her lower range.  It's the roundness, the fullness, and the depth of her voice, along with her ability to create and access an enormous amount of resonance.  This further defines Diana as a "dramatic contralto", and a "dramatic contralto", the deepest, darkest, and most powerful contralto voice type and the rarest of the rare contralto voice types.
    What most people want to know is, how does Diana do it? How can such a young female singer achieve such a low, rich, deep, and profound sound?  Without actually scoping her vocal tract while she is producing those low notes to see what is happening within her vocal tract, the general conciseness of many vocal professionals is simply attributing Diana’s ability to her winning the genetic lottery.  She was just born with unique vocal anatomy.  Diana’s vocal folds appear to be longer and thicker than most female singers.  Her larynx also appears to be larger and her pharynx similarly appears to be larger than other female singers.  This unique vocal anatomy gives Diana Ankudinova the ability to produce those low, deep, rich, full notes, but without actually scoping Diana’s vocal track there is no way to be 100% sure.
    Diana is also a real polyphonic singer which is exceedingly rare for someone so young to have accomplished.  A singer who has mastered this polyphonic vocal technique can create one, and sometimes two, different tones at the same time which adds to the harmonic overtones and undertones that can make it sound like more than one voice singing. This polyphonic ability is why some people mistakenly believe Diana Ankudinova is using some form of electronic voice manipulation or pitch correction software to alter or adjust her sound. Others believe another person is singing off stage in the background, or she is lip-syncing over a previously recorded vocal track that was altered or modified. There is no artificial manipulation of Diana's voice of any kind going on at all. Neither is anyone else singing off stage nor is she lip-syncing to a vocal track.  The other vocals you are hearing is a vocal backing track used to fill in and round out the performance along with the musical score, which is also on a backing track.  Diana Ankudinova and only Diana Ankudinova is singing “Can't Help Falling In Love”.

Посмотрите на лицо Дианы, она не поет, она там живёт в этом её Мире.
Так передать чуства, а не пение может только Диана.

Here are three reasons why Diana (the Queen of Goosebumps) doesn't sound human. First, she is a contralto, which is the absolute rarest type of female voice. It allows her to sing very dramatic/powerful, very (I mean VERY) deep, very dark, very rich. Second, she has a spectacular larynx. She's been called the vocal Eighth Wonder of the World. Third, she is polyphonic, which means she can produce multiple harmonics within her voice at the same time. This is what allows her to sound like two people at once. (more below) When you add all that up you basically get a person who creates her own auto-tune. She doesn't need electronic auto-tune. She IS her own auto-tune. And the effect when you hear her is totally mind-blowing. It's like she's singing right through you, like a sword straight into your soul. Literally NOBODY else on the planet has a voice like hers. She's not one in a million, she's one in seven billion. On top of that, she's only 18 here!!!

Be sure to play this loud in the house. Her polyphonics and timbre will challenge your speakers and it becomes a full body experience to be rattled by. Your life just changed today. She is incomparable and astounding in all her performances. Enjoy the ride 😊

Dramatic soprano who can sing with polyphonic overtones.  Most unique female voice on the planet.  And only 19.

Great Reaction ! You have just witnessed "The World’s Greatest Vocals".  Diana (DEE-ana) is a True Dramatic Contralto, very very rare, with Polyphonic overtones. She can sing Two notes at the same time. She is from and Lives in Russia. Super Award-Winning Artist. She sings in 6 different Languages, Diana has over 300 Perfect Performances. She is 19yrs old. She has Millions of Millions of Super Fans. We All Love her so much. I have watched over 600 hours myself. She has changed my Life. Please read her story if you Really want to be Blown away. She was left out on the winter street at the age of 3 with a broken Collar bone, was orphaned and couldn't speak, You can take it from there. Simply Amazing!  She makes every Performance her own. Every music video becomes very special. Please become a Super Fan along with us , and Thank God he Blessed us with  her.

Peter Barber is an operatic bass singer and he came to the same realization you did re: her tongue position. He thought maybe, just maybe, she was doing some tongue manipulations to get that extremely dark tone. He went back to watch and was stunned. "Her tongue is perfectly flat!" To say he was flabbergasted was an understatement. 😃

Да! Именно такая реакция у всех кто смотрит это великолепное выступление Дианы впервые! И это нормально! Продолжай! Дальше интересней!!!

Welcome to the world of the most insanely unique and talented vocalist of our time - Diana Ankudinova. The official video from her channel does not cut off at the end (and has subtitled judge reactions): https://youtu.be/M-znD6QKbrg You are in for one amazing journey!

"Dee-ana An-ku-DEE-no-vah".  Accent on middle syllable.  She is actually more comfortable in the low registers and has worked hard on the upper.

A polyphonic dramatic contralto with amazing range and control. The judge at the top, standing up with the beard and tears in his eyes is Yusif Eyvazov, a famous opera tenor. What does it say about her performance if she could move him to tears.

Диана Анкудинова великолепна!!! 💎
Исполнение фаниастическое!!! 👍💯
Браво Диана!!! 👏👏👏👏👏👏👏👏

She almost covers 3 full octaves here..  C3 to Bflat5.. she is a fantastic yodeler too.. thanks for giving Diana a listen

Diana's story is quite sad, but give her credit for overcoming her beginnings. There is a plethora of songs she has done. In this same competition, check out her performance of The Crow!! Also, an earlier work is "Rechenka" which was done when she was 14. She sings a classic Russian folk song and making sounds of owls and forest creatures while she's singing.

Диана разная и очень уникальна! Просто наслаждайтесь! Спасибо🥰😍😘

Thanks for the reaction to Diana and the analysis. A slight correction, this performance wasn't on "You Are Super" but on a show called "ShowMaskGoOn", an offshoot of the Russian version of "The Masked Singer". Diana did appear on "You Are Super" in 2018, aged 14 and 2019 when she was 15. Here in Autumn 2021 she was 18 - born 31st May 2003. "ShowMaskGoOn" ran for 9 weeks with the same 9 singers (including Diana) singing in different genres each week.

If you were to look at Diana again, I would suggest two performances from "You Are Super" to start with. Firstly, aged 14, "Rechenka" (Russian folk song) - https://www.youtube.com/watch?v=fEcvVINA304 and secondly, aged 15, "Wicked Game" (Chris Isaac cover) - https://www.youtube.com/watch?v=kt78je5hD0k

After those, go to Diana's own channel and take your pick. Incidentally, the video you reacted to is a pirate copy which as you noted cuts off the final note - the original on Diana's channel also has the comments of her fellow singers together with that of the guest judge Yusif Eyvazov (the chap with the beard who stood up) - he's an international opera singer and is married to the mega soprano Anna Netrebko, so he knows a thing or two!

Diana and Dimash need to sing together.  They are the 8th wonder of the world.

That voice is Diana Ankudinova! The best!

Самая уникальная певица на Планете Земля. Горжусь нашей Дианой! Вам спасибо за искренние эмоции.