If your phone is truly new (meaning purchased brand new via Apple or authorized retailer including from carrier) and it’s not an exaggeration that it is running like an iPhone 4 (which absolutely would be an extremely unusual thing if this is truly the case) then you need to take it to your nearest Apple Store or authorized repair facility to have it inspected to see if you have an issue that is beyond the iOS update.
As far as the keyboard…go to Keyboards in settings and see if one of the keyboards active is labeled Bilingual. You can select edit and delete it if you don’t want it to be there at all. Also check that the primary keyboard (the one at the top of the list) does not have another language added. If it does, remove that language so that keyboard does not function as a multilingual keyboard.
After updates and noticing new features or changes it is a good idea to go through the settings to see what may need to be adjusted to better fit your personal needs. The new features are not bugs or unimportant (there are many users that would actually appreciate the new bilingual options). Because you can change your settings it is not being forced on you and does not make it useless for the masses just because you may not be interested in those changes. The same can be said for the photo app changes. There are options to customize it to better fit your preferences but for every person that complained about it there were others that loved it. I fall on the indifferent side of it because I don’t mind change and took the time to adjust things so it was more useful for me. But I digress
And you do realize that Samsung also makes changes to features you may love and users complain. Updates means changes are inevitable so while you have every right to switch to Samsung if you think it will better fit your needs you need to realistically prepare your self for when they do a change that you don’t like and deem useless. Of course you can always decide to change to a different brand every time they do change something you don’t like. Or…you can learn the new features and customization options to make the new work for you. Your choice. If you have any other specific support questions on your issues feel free to share them so that some of us can try to help. Or contact Apple Support directly.