How do these two parts of a sentence relate? [closed]

I read this in Word by Word by Kory Stamper;

It will become clear to you, in the space between heart beats, why you are having a hard time with this entry: it is because you realise now that you do not in fact actually speak English – that the words you are reading are in some low German dialect and you are no longer certain that they mean anything.

It is an account of a lexicographer, to make the sense of "entry" clear to you. But I want to ask: does it mean that you are so obsessed with writing an entry that you forget the language you speak? And, more importantly to me, how does it relate to the part of the sentence after the dash?

This is the usual thing that happens to any frequently-repeated chunk of language. It's called "fatiguing" the system. Say any phrase or sentence out loud 25 times. As you listen, you will find the words becoming just sounds to you, until all you hear is their rhythm and acoustics.

Since you already know what the words mean, repeating the language stimulus doesn't necessarily load the language interpreter as usual, and interesting other programs can be accessed, often with surprising results. The phenomenon has been utilized for millennia; this is what's behind many mantras and chants.

In this case, a fatigued lexicographer loads an etymological analysis routine, with predictable results.