Keyboard completing (badly) my words and sentences for unknown reason

Hello everyone,

My keyboard started acting weird since the last Catalina update. It's like it tries to complete the words I'm writing but with a delay, which creates weird sentences... It happens randomly but often when I start a sentence.

For example, if I type "Hello everyone" it completes the sentence before I'm done writing: "Hello evello evryone"

I looked up in my preferences and disabled all the keyboard parameters like auto-correction or auto-completion but nothing changed. This happens in all my softwares.

Thanks for your time.