The “Core” of English Words
For the version of English we speak today, in terms of vocabulary rather than syntax/sentence structure, the words that come from what you just heard are primarily from the “core” English words of the Anglo-Saxon and Scandinavian influence on English.
These words are some of the connective tissue of English that we rely on so often today: a, can, the, to, is, etc.
But also other very common words are from this core: warn, think, car. And many of the closest to material reality: bread, milk, sun.
The most frequent words we use come from this core. The more people use the core vocabulary, the more likely readers will find it as simple and straightforward.
For some speakers, these are the words that are associated with early memories of speaking English and are the sorts of words they are most accustomed to using.
French Influence
After the Norman Conquest (i.e., France colonizing England way back), French had a large influence on the development of English. French, for a long time, was exclusively the language of the state (and, thus, of writing). However, over time, borrowings occurred that influenced English speaking and writing quite a bit.
Many borrowings from Old French, today, are associated with elevation, elegance, beauty, etc. Words like: autumn, glory, stunning, capture, cherish, adorned, accented, auburn, authenticity, acquire.
These are the sorts of words that are more likely to be used in perfume commercials, romantic texts, or anything that might want to sound a bit elevated in terms of grace/class/etc.
Latin and Greek Influence
Several centuries from the early 1000s through the Renaissance and further out, much scholarship was written exclusively in Latin and some Greek. Thus, many of the words associated with knowledge and with formality are borrowings from Latin and Greek.
Words like substance, corporeal, composite, finite, sentient, cerebral, fact, explain, necessitate, crisis, appropriate, external, scheme, system, obstruction all come from Latin and Greek.