When using a resource pack that includes a language file, many strings won't display apostrophes if they contain more than one. This problem is seen in Forge 35.1.13 with no mods installed; in a vanilla Minecraft profile these strings display as expected.
For instance, the line
"menu.singleplayer": "One 'player'"
causes the singleplayer button on the main menu to display as One player with Forge. Without Forge it displays as One 'player'.
I've created a small resource pack that replaces several strings in en_us.json with ones that include multiple apostrophes, including the one above. For reference, it also includes two strings I found that aren't affected—a death message and a command output; these display correctly. Make sure the language is set to "English (US)".
