Initial screen just went wordless

This is almost certainly a texture resource pack. They're capable of changing how the loading screen is displayed. Click on the third button. This will bring you to the settings screen:

In the General (last) section, the fourth option (at least for me) is Global Resources:

Notice how the Minecraft Texture Pack doesn't have a lock icon on it. Also nothing happens when you click it. You want to disable all other texture packs in the Active Packs section. Do this by clicking on them, then clicking on the - button (which is the left of 4 buttons appearing under the resource pack info). This doesn't delete them, just disables them. After that, it should be back to normal.