Davening is not in Hebrew, it is לשון קודש. Most people who learned a Yeshiva or Beis Yaakov know more than enough to understand the words. In addition many also teach peirush of davening. I know that mine and my children’s did.
There are many readily available siddurim with translations in manor languages for those who do not understand לשון הקודש well enough.
More important than just understanding the words is meaning what one davens.
Not understanding the words is often not the real reason why those who talk by davening do so. Most often it is Attitude. The same attitude which may be the reason why they do not know what they are saying. Even when they should know what the word mean.