It says: "let the two glittering stones
one in red
one in blue
connect the past
two friends sharing power
open a window to a new world that glows
the next world waits for you"
Those symbols are braille letters. To decode them, just search "braille decoder" in google. They give you instructions on what to do to get into the next room. In the next room is one of the regis. (Regice, Regirock, Registeel)
this is the translation:
Look up a normal braille sheet on the internet
A person can read the braille in the Secret Chambers in Pokemon Sapphire by translating the braille to the corresponding letters of the alphabet. A person will be required to dig to reach the appropriate area of the chamber.
You can research "How to read Braille" for more information.
Each braille or cell is made up of six dots position. Island 6 is for obtaining the sapphire. Also it uses the power of dreams.
It's in the sealed chamber which is in route 134.
Braille
In Pokémon Sapphire, the Braille tablets are found in the Cave of Origin and the Sealed Chamber. To read them, players need to use the Braille translation guide, which assigns a letter to each Braille symbol. By deciphering the Braille, players can uncover hints and instructions related to the Regi Pokémon and unlock their locations. Players often refer to online guides to help interpret the Braille effectively.
In Ruby and Sapphire the braille reads: "With new time, hope and love, aim to the sky in the middle." This means use Fly in the center of the tomb. In Emerald the braille reads: "Those who inherit our will, shine in the middle." This means use Flash in the center of the tomb.
dotted hole is on the south side of six island. (the sapphire is in there) a little extra info: dotted hole does have braille in it.
after you read the braille press down down down down and use fly then the door will open