I believe much of the Ancient writing that we see in Atlantis (and possibly in Stargate once the Atlantis series began running concurrently) can be translated to english. To make the translations we have the ancient to english dictionary (source: stargate wiki):
#Atlantic Gateroom Stairs#
Atlantic Gateroom Stairs
(Note: the writing on the main stairs translates to English, but the ancient writing on the stairs up to the platform the gate is on doesn't seem to translate to meaningful English sentences.)
We hold these as the truth
A hearty welcome to those of other worlds
Visiting our home for the first time welcome again
To those returning you have been gone too long and your
Absence has weighed heavily on our souls we are
Whole again that you are among us and we celebrate you being here again
As we leave for distant worlds we pledge to respect the lands of
Our neighbours and to act with integrity as ambassadors in peace time
Of our people travellers with open hearts will always be welcome refugees
From tyranny may seek shelter under our roof and our people will lay
Down their lives to protect the weak and the just let this be our pledge to those
Inhabitants of this world and all we may ever know we will always strive to
Come in peace as we go in peace and you will be welcome on our shores forevermore
#Puddle Jumper Console#
Puddle Jumper Console
From an answer I gave to another question on why they don't cloak the jumpers before entering the stargate we have more of the ancients leaving messages in english with ancient letters.
Two images are here, taken from the Season 1 episode, The Defiant One *, show the left and center of the console, respectively,
We get the following translation
Gate protocols must be set before launch sequence.
Never attempt gate reentry when in cloak m??? [mode?]
#Zero Point Module Interface#
Zero Point Module Interface
We also have the following image from the Season 1 episode, Before I sleep. The writing on the zero point module station (at the bottom of the picture) translates.
STAY CLEAR
#Stargate SG-1: Avalon Puzzles#
Stargate SG-1: Avalon Puzzles
From the Stargate SG-1 Episode Avalon, Part 1 the team encounters two puzzles with ancient writing (which Daniel Jackson gives us the translations for during the episode):
The first (the Vala, Daniel Jackson puzzle in the episode) says
THE TREASURE IS NOT IN THIS POT
THE UNIVERSE IS INFINITE
The second puzzle (the Cam / Teal'c puzzle) says
REFLECT ON THE EIGHTFOLD PATH
