Too many english speakers, so I think that's why you did not catch that.
One of the commenters in the general discussion about iOS 11 bugs said that it was not possible to type accented characters on iOS 11.
I got curious and today have investigated it further. It seems we do have a bug.
1- Enable portuguese / french / spanish / any other keyboard from languages which support accented characters.
2- Open any edit field and select one of these keyboards.
3- In classic typing, you double tap and hold a letter which may have an accented variation such as a that can have an acute and other accents and a popup opens with these options, this is working.
4- But in professional typing you can not make a double tap and hold because if you lift your finger to make the second tap the letter is entered.
5- The way it consistently worked until iOS 10 was you place your finger on the letter and let it stay there for a couple of time, usually one and a half seconds or so and the same popup with the accented variations would open, so that you move your finger to the desired option and then lift it to enter the appropriate character.
6- But this do not work anymore.
This is an extremely serious bug for those who have to type in these languages on a daily basis, because many times classic typing is not a productive enough option and the professional typing is preventing us from typing the characters we need in the texts.
if you can, please confirm this and fill a bug on your directory, I can not do it from my user account.
There is though a work around I have found.
1- In professional typing, find the letter to be accented.
2- Lift your finger, you will enter that letter. But do not move your finger, just let it away from the screen but at the very same position it was.
3- Now double tap and hold.
4- You will see the popup. Move your finger to the appropriate character and lift, you will enter the correct character.
5- Blearg ... now move one character back with the rotor and delete the non accented character you entered when you first lifted your finger...
6- I suppose if you double tap and hold directly where the letter is you can skip the steps 1 2 and 5 but this is the way direct touch typing works not the way professional typing does. This is a bug that needs to be fixed.