When we learn the grammar of a language, native speakers seem to slow down their rate of speech.
The same is true for this nonsense sentence, “The gladdled tallywagle strupedly zloggled through the sloggity wonkeys.” Although we may not know the words, our grammar tells us from what class to expect each word.
For example, “gladdled” is an adjective, “tallywagle,” is a noun; “strupedly,” is an adverb; “zlogged” is a verb in the past tense, etc.
When we first learn a foreign language, it appears to us that the native speakers all talk much too fast.
But after we have begun to master the grammar, the native speakers mysteriously seem to slow down.
Actually, it is we who are speeding up and processing language faster, thanks to our newly developed grammatical expectancies.