Sit and sentar

They both likely came from the indo european form of sitting.  But sentar got conjugated by the latins while the english version bypassed.

So sit conjugates differently than spanish would have it. Most english verbs have simple tense changes internal to the word: sit,sat, eat,ate, come came.  Lend,lent.  The spanish term for lending seems to come from a different source, later.

These are not latin conjugations in tense.

They are tense changes that come from a primarily vocal tradition. The idea is the maximal separation of vocal sounds for the most common everyday vocalizations. So, we originally were just nuanced 'barkers', probably homo erectus could do some of this.

Rhyme and contrast made the vocal traditions last, they get lost if the vocalizations are not a big part of society. We can imagine the time when poets and singers ruled the communication medium.  Opera today was likely the formal method of education in the pre-literate days, 4000 years ago.

Parchment made a big difference, it was a huge gain in organization far spread commerce.