///I'm not sure if this is the right question to put to Sqad or not. ///
and neither am I ;-)
It is extremely common to see people reading who automatically have learnt to read in this manner and it is part and parcel of their reading technique, however, this does not seem the case with you.
In your case, this has occurred recently as a new phenomenon and i also assume that your speech hasn't changed, i.e slurred in any way or that you have any weakness of your limbs.
There could be a simple explanation in that you need to formulate the words with your lips to make sense of the sentences.
However, if you were my wife, in your situation i would ask my GP if in his opinion a Neurological opinion should be sought. I am sure that all will be well, but it would be nice to get expert advice.
Google..........Alexia......but don't get bogged down with the minutiae.