I suggest "Spinning Starlight" by R. C. Lewis.

This is the description from Goodreads:

Sixteen-year-old heiress and paparazzi darling Liddi Jantzen hates the spotlight. But as the only daughter in the most powerful tech family in the galaxy, it’s hard to escape it. So when a group of men shows up at her house uninvited, she assumes it’s just the usual media-grubs. That is, until shots are fired.

Liddi escapes, only to be pulled into an interplanetary conspiracy more complex than she ever could have imagined. Her older brothers have been caught as well, trapped in the conduits between the planets. And when their captor implants a device in Liddi’s vocal cords to monitor her speech, their lives are in her hands: One word and her brothers are dead.

Desperate to save her family from a desolate future, Liddi travels to another world, where she meets the one person who might have the skills to help her bring her eight brothers home—a handsome dignitary named Tiav. But without her voice, Liddi must use every bit of her strength and wit to convince Tiav that her mission is true. With the tenuous balance of the planets deeply intertwined with her brothers’ survival, just how much is Liddi willing to sacrifice to bring them back?

The book has a dark blue cover with a silver outline of a swan. It was published in October of 2015, so fits the time frame.

I suggest "Spinning Starlight" by R. C. Lewis.

This is the description from Goodreads:

Sixteen-year-old heiress and paparazzi darling Liddi Jantzen hates the spotlight. But as the only daughter in the most powerful tech family in the galaxy, it’s hard to escape it. So when a group of men shows up at her house uninvited, she assumes it’s just the usual media-grubs. That is, until shots are fired.

Liddi escapes, only to be pulled into an interplanetary conspiracy more complex than she ever could have imagined. Her older brothers have been caught as well, trapped in the conduits between the planets. And when their captor implants a device in Liddi’s vocal cords to monitor her speech, their lives are in her hands: One word and her brothers are dead.

Desperate to save her family from a desolate future, Liddi travels to another world, where she meets the one person who might have the skills to help her bring her eight brothers home—a handsome dignitary named Tiav. But without her voice, Liddi must use every bit of her strength and wit to convince Tiav that her mission is true. With the tenuous balance of the planets deeply intertwined with her brothers’ survival, just how much is Liddi willing to sacrifice to bring them back?

The book has a dark blue cover with a silver outline of a swan. It was published in October of 2015, so fits the time frame.

I guess so, except for the whole Khua part. Their word for the portals, I suppose.
Their word. Now that I know what to call them, maybe I can get some answers to avoid recklessness and inform my actions, like Jahmari suggested.

I suggest "Spinning Starlight" by R. C. Lewis.

This is the description from Goodreads:

Sixteen-year-old heiress and paparazzi darling Liddi Jantzen hates the spotlight. But as the only daughter in the most powerful tech family in the galaxy, it’s hard to escape it. So when a group of men shows up at her house uninvited, she assumes it’s just the usual media-grubs. That is, until shots are fired.

Liddi escapes, only to be pulled into an interplanetary conspiracy more complex than she ever could have imagined. Her older brothers have been caught as well, trapped in the conduits between the planets. And when their captor implants a device in Liddi’s vocal cords to monitor her speech, their lives are in her hands: One word and her brothers are dead.

Desperate to save her family from a desolate future, Liddi travels to another world, where she meets the one person who might have the skills to help her bring her eight brothers home—a handsome dignitary named Tiav. But without her voice, Liddi must use every bit of her strength and wit to convince Tiav that her mission is true. With the tenuous balance of the planets deeply intertwined with her brothers’ survival, just how much is Liddi willing to sacrifice to bring them back?

The book has a dark blue cover with a silver outline of a swan.

I suggest "Spinning Starlight" by R. C. Lewis.

This is the description from Goodreads:

Sixteen-year-old heiress and paparazzi darling Liddi Jantzen hates the spotlight. But as the only daughter in the most powerful tech family in the galaxy, it’s hard to escape it. So when a group of men shows up at her house uninvited, she assumes it’s just the usual media-grubs. That is, until shots are fired.

Liddi escapes, only to be pulled into an interplanetary conspiracy more complex than she ever could have imagined. Her older brothers have been caught as well, trapped in the conduits between the planets. And when their captor implants a device in Liddi’s vocal cords to monitor her speech, their lives are in her hands: One word and her brothers are dead.

Desperate to save her family from a desolate future, Liddi travels to another world, where she meets the one person who might have the skills to help her bring her eight brothers home—a handsome dignitary named Tiav. But without her voice, Liddi must use every bit of her strength and wit to convince Tiav that her mission is true. With the tenuous balance of the planets deeply intertwined with her brothers’ survival, just how much is Liddi willing to sacrifice to bring them back?

The book has a dark blue cover with a silver outline of a swan. It was published in October of 2015, so fits the time frame.