It's like any appliance ... if you have to wear it, you will get used to it and after some practise you can talk and eat without much hassle.  It's only a problem if you let it be one.

I was given a passage, called the Rainbow passage to practise speaking out loud, several times an hour, after I had my expanders bonded.  To begin with there was lisping and spitting and  I felt like I was choking when I ate.  With practise, I was back to talking and eating easily ... within a week.

Besides, a Fraenkel is hardly the most restrictive appliance around, speachwise.

But it's often written on orthodontic sites that you can talk very easily with Fraenkel appliance because of its thin construction?!

Aber auf KFO-Seiten wird immer geschrieben, dass mit Fränkel-Spangen das Reden sehr einfach wäre, da nicht so klobig?!

I have had a thick bite plate for a few years and I dont often take it out. If I do take it out it is not easy to talk clearly and I stumble over words.
Some time ago I answered the phone without it  and had to go and put it in before I could say much as I could hear that I didnt sound right.
I have an activator as well and it is quite easy to talk with it in now I have got used to it.
I remember seeing a teenager with an activator at the airport but he took it out everytime he wanted to say anything.