Learn English – 1700s term for “a technology”

The most probable term would be "geek", as in "computer geek" (roughly "computer whiz").
(not the US geek from fifty years ago, as the lowest form of circus performer, who did horrible, demeaning things).
Even though a geek is not necessarily smart or into computers, but can be in general a "weird person", the only usage of geek I know in French culture is related to computer.

This thread mentions:

"Nerd" has several meanings/usages.

• One is that of a studious intellectual, meant to be negative but carrying a whiff of envy.
• The other is "awkward pain in the neck".

One (non-official) difference between nerd and geek (in the computer field) could also be in term of general activity:

• "Nerd" = producer
• "Geek" = consumer

Eg. a nerd creates video games, a geek plays the video games.
But those two terms certainly cannot be limited to this simple interpretation.

That being said, I thought the remark from John Hodgman was quite accurate:

Comedian John Hodgman recently spoke at a Washington DC press dinner, following Barack Obama, touting Obama as the first Nerd President, since Obama had admitted to collecting comic books and being a fan of Star Trek. Obama's Nerd intellectualism was contrasted to the "Jock" mentality that had defined the Bush years.
In the midst of this speech Hodgman suddenly referred to Obama as a geek, quickly adding this aside:

"And to those who say, 'Wait, there's a difference between nerds and geeks,' I answer, 'Shut up, nerd!'"

Nicely illustrated by phdcomics:

Consider if the letter u being represented as v (as I pointed to earlier) — this would be a monumental change which would be unlikely to appear in the modern era, simply because of the number of standards (i.e. ASCII, Unicode, most all information exchange definitions, fonts, most programming language definitions, etc) which would be affected would be enormous.

I don’t think this is a particularly useful example for your hypothesis. If the English language needed to create another letter distinction such as the one that evolved between u and v, many of these pragmatic considerations might be avoidable if we simply borrowed another commonly-available glyph (from another language, a ligature or currency symbol, or whatever) instead of creating an entirely new letter shape. After all, that’s pretty similar to what happened with u and v: as you point out, the two shapes started off as orthographic variants of the same letter. In the 1800s, it would have been extremely expensive to add a new glyph to the metal type on printing presses — so when a distinction arose, they stuck to the glyphs everyone already had on hand.

Spelling reforms might be another “systematic change” in the English language. While it’s true that popular dictionaries have regularized formal spelling in the past couple centuries, that shift began before your hypothesized timing. Also, note that informal spelling has resisted such change; the orthographic shorthand often used in SMS and instant messaging represents one obvious example of the continuing evolution of accepted spelling in informal contexts.

You’ve indicated that adopting new vocabulary isn’t a systematic change, so widespread importation of words when English is forced to co-exist closely with another language doesn’t seem to be a relevant issue either. You also mentioned “structure words”, but those haven’t changed noticeably in the last couple hundred years, either. I’m pretty sure there haven’t been any major changes in the acceptability of different syntax structures in modern English, although I don’t have handy data for that one.

I’m unsure how to get solid data about the frequency of significant morphological and grammatical changes on this 100–200 year timescale, so I can’t address those aspects.