The wait is almost over. Answers about Samsung's foldable phone -- rumored to be called the Galaxy X, Galaxy F, Galaxy Fold or Galaxy Flex -- will come on Feb. 20. On Monday, Samsung issued a teaser video saying, "The future of mobile will unfold on Feb. 20, 2019," alongside imagery of Korean and English words that spell out "the future unfolds" sliding along an invisible curved surface. 

While the video doesn't give away much, it does confirm that Samsung will use its Galaxy S10 launch event (how to watch live) to also talk about its foldable phone in detail. At this point, we expect to see more than the flash of folding phone prototype Samsung briefly waved around at its developers conference this past November. The Wall Street Journal reports that Samsung will trot out a fully fledged unit to show off. 

The company's foldable phone is slated to arrive in the first half of 2019. It's already generating buzz, and for good reason. Along with 5G, foldable phones are widely regarded as the next big thing for smartphones in 2019. 

A foldable design promises to expand a handset's screen size while keeping the device portable enough to carry around. As the forefront of a bold new design era, foldable phones are also seen as a way to shake up renewed interest as people hold onto their devices longer and phone sales slow.

Samsung may be the biggest dog in the race, but competitors are hot on its heels. Xiaomi, a Chinese brand relatively unknown in the US, has already challenged Samsung with a new kind of foldable phone design before it's even announced.

Although we know more now than we did back in November when Samsung's foldable phone became real, what we've seen of the device so far has raised more questions than answers. Here's what we know, what we think and what's still to be uncovered.

Samsung did not respond to a request for comment.

Galaxy X? Or, more likely, Galaxy F, Galaxy Fold, Galaxy Flex

The Galaxy X and Galaxy F were two early front-runners, and a recent report from the Wall Street Journal suggested that Samsung will pick a name in the "F" category. Galaxy F, Galaxy Fold or Galaxy Flex are all possibilities, although within CNET's corridors we agree they're mostly all safe choices (one is downright bad). 

Yet after Samsung' video Feb. 11 leak, I'm inclined to think "Galaxy Fold" could win out, since Samsung chose the phrase "the future unfolds" and not something with an X in it, like "the future is exciting."

Although Galaxy X sounds a lot cooler and less prone to negative connotation -- "F" stands for "fail" and for a common four-letter curse word -- it makes sense for Samsung to avoid "copying" the iPhone X. However, "X" could legitimately might mean "extra," "exciting" or "10," since there are nine Galaxy S phones out and this is, after all, Samsung's 10th anniversary Galaxy S year.

Read: Samsung's foldable phone faces 10 big issues

What's this about a foldable phone for gaming?

Samsung was granted a patent for a foldable phone design that includes physical gaming controls like a D-pad and buttons. Sounds insane, right? Perhaps, but the design combines two major trends, foldable and niche gaming phones like the Razer Phone 2 and Nubia Red Magic Mars. 

Even if we don't see these controls on Samsung's first folding phone, it's a glimpse into another way this large, hybrid device could work.

Wait, what's a foldable phone anyway?

If we go by Samsung's definition, a foldable phone is a device with a cellular connection (hence the "phone" part) that looks like a tablet when it's fully opened and can close to look like your usual phone. 

Samsung's prototype has a tablet-like screen that closes inward like a book, but Royole's FlexPai, another foldable phone, has an outward-folding screen, which means the "screen" is on the outside. Xiaomi's upcoming foldable phone bends back on both edges so that the middle part of the screen becomes the size of a typical phone. There's no single definition.

Didn't ZTE make a foldable phone?

Last year's ZTE Axon M was an early version of a foldable phone that attached two separate phone screens through a central hinge. Samsung's foldable phone (and Royole's FlexPai) appear to have unibody displays that fold at the midpoint. A magnet secures the FlexPai's screen in the "closed" position.

We can credit the Axon M with exploring different new ways to use a dual-screen device; Royole has already adopted some of these, for example, mirroring the contents of both screens so people on either side of a table can watch the same video clip. ZTE could very well come up with a second-generation foldable (or "foldable") phone, though it's competitors like Huawei and Motorola that are rumored to get there first.

What's the benefit of a foldable phone?

There are two main advantages. First, a foldable phone can more than double your available screen space. For example, Samsung's model has a 4.5-inch display that you'll use when it's closed. Then the inside opens into a 7.3-inch screen. You could argue that you have the equivalent of three displays to work with.

A larger screen gives you an expanded viewing surface, but it also unlocks different ways that you can use your device. For example, Samsung's foldable display will let you multitask in three areas at once. ZTE's Axon M lets you use the entire screen for one app, load a separate app on each screen, or mirror the same app on both screens.

Thanks to Google's official Android support for all foldable phones, apps on the foldable Galaxy phone will be able to take advantage of three active windows on that 7.3-inch interior display. now there's just the question of killer apps.

What happens when you open and close Samsung's phone when you're using an app?

Like the Royole FlexPai, this foldable phone will automatically transfer the app or screen you're looking at in the folded-up "closed" position to the "open" position, and vice versa. 

We noticed some lag here on the FlexPai, but haven't had a chance to see how Samsung will handle the transition.

Xiaomi's video shows a simpler solution. If you're closing the phone by folding under the edges of a larger screen, you never truly lose the screen you're on, so in theory you're not switching between screens at all, just configurations.

What's so great about Samsung's display?

Samsung created a new display for its foldable phone, the Infinity Flex Display. The company said that it had to modify the usual layers that are part of any display (this is what lights up the "screen" you see on your phone). 

All displays are made of layers, but they're usually stacked and unmoving. The Infinity Flex Display uses a new adhesive that Samsung developed to laminate the display layers so they can flex and fold hundreds of thousands of times.

Samsung also needed to make the Infinity Flex Display thinner than any other mobile display. It cut the thickness of the polarizer layer, which helps make the screen legible, by 45 percent.

The Infinity Flex is made of polymer, which is to say, a type of plastic. It's possible that the 4.5 exterior screen has a Gorilla Glass cover material like the Galaxy S9 and Note 9 phones. 

Will we ever get foldable glass?

We hope so! Glass is typically seen as a more premium material than plastic. CNET was the first to report that the company behind Gorilla Glass, Corning, has been working on creating superthin glass that can bend.

"To go to a tight bend radius, you have to go to a glass that's much, much thinner than what you have today, and some of the glass we have in our laboratory is thinner than a human hair," said Polly Chu, technology director at Corning.

Right now, the company is still developing its flexible cover glass -- we're just not sure when it'll be ready to go on sale. While we could see it on Samsung's first foldable phone, there's also a good chance it might not appear until 2020 at the earliest. We'll have to sit back and see.

When will Samsung's foldable phone go on sale?

Samsung told us that the phone will arrive in the first half of 2019. In November, it said that mass production would take place in the "coming months." Barring any disasters, the foldable phone will likely start selling in 2019, early rumor pegging March as the release date. 

Again, while we do expect a closer look at the Galaxy S10 launch, Samsung is likely to hold a separate Unpacked event to introduce its first-ever foldable phone.

How much will it cost?

It's easy to guess that this will be an expensive device. Gizmodo UK, citing a source it says it "has verified works for Samsung" reported that the foldable Galaxy phone could cost between £1,500 and £2,000. That converts to roughly $1,930 and $2,570 (AU$2,700 to AU$3,600).

Those prices slot in with what we already know of foldable phones. The Royole FlexPai's aimed at developers costs $1,318 for a device with 6GB RAM and 128GB of internal storage. The version with 8GB RAM and 256GB storage goes for $1,469.

Since Samsung's Galaxy Note 9 for power users starts at $999, it's a logical guess that a cutting-edge foldable phone would easily start at $1,500, if not more. We can expect device-makers like Samsung (and Royole) to justify high prices based on total screen real estate. After all, they reason, you're getting a tablet and phone in one -- and phone prices are only getting higher.

What's the battery life like?

Samsung aims to give its foldable phone battery life that lasts as long as current Galaxy smartphones, said Jisun Park, the engineering director and head of the system software group for Samsung's mobile business. That's despite the fact there's more active screen to drain the battery. The US version of the Note 9 lasted for an average of 19 hours, 20 minutes in CNET's looping video drain test.

Where's the battery going to go?

We don't have access to the design particulars, but batteries don't bend. Expect a large battery to sit on one side and many of the other components to balance it out on the other. One major complaint we had with the ZTE Axon M was that it felt imbalanced with the half containing the battery drastically thicker and heavier than the other half. Samsung will have to watch out for that.

Is that picture what the foldable phone will really look like?

Definitely not. Samsung showed off a prototype model, commenting that the real parts were hidden within. Samsung isn't ready for the public -- or competitors -- to see a final design.

If there's one breadcrumb officially left us about the foldable phone's eventual shape, it's in the new One UI operating system. The company mentioned that the rounded rectangular edges that form a major design motif are meant to match its devices' rounded edges. The prototype foldable phone has 90-degree edges and thick bezels. We can anticipate a softer look.

What are the foldable Galaxy phone's hardware specs?

The 4.5-inch external screen, 7.3-inch Infinity Flex internal screen are about the only hard specs we know. We don't have details about the camera, the battery capacity or processor. 

However, I'd put my money on the foldable phone using the Qualcomm Snapdragon 855 that we know will also be in the Galaxy S10. A phone that's balancing battery resources and performance across two screens will need speed and power efficiency to keep the battery life from plummeting as you switch between screens throughout the day.

Storage size, a headphone jack, external storage capacity and waterproofing are still unknowns.