The first thing you should check is that you have added the name to the "en_us.lang" file. Make sure that you have an entry for the item whose name is showing incorrectly. Also, make sure that you typed the line correctly, so if the unlocalized name is 'myPickaxe', the entry should say "item.myPickaxe.name=". If it's a block, it will start with the word tile instead of item. If you can't remember what the line is supposed to say, check back to that part of the video.

Did this answer your question?