If it can help you, you could use sprites for letters, each letter being a different animation frame for the same sprite.
Then you move an overlay sprite by lets say 32 pixels (Letter sprite is 32 pixels too)
If OverlaySprite is positioned in A then it can move only if X is greater or equal than A.XPosition.
I did something similar for a menu with around 10 lines of code or a bit more so should hopefully be fairly easy.
Good luck!