I don't know about that, the brain is an amazing thing.
When I was learning Afrikaans, my final mark was 48% so I did know only about half the words.
However!
When I came across words that I didn't understand at all, my brain did one of two things.
Abandon the whole sentence all together or figure out the rest of the words and then find the context and fill the gaps.
if I had no idea what "How English looks to people learning it" meant as I'm from another language, I would start with
___ English ___ to ___ ___ it
to and it are basic words and English is the name of the language
maybe I learnt look and people in one of my first English classes
___ English look to people ___ it
I would consider this point to being the 50% point where I either have no idea where to go or I map out the possibilities in the context.
what can I do to English?
it could be reading, writing, learning, etc
Let's go with my Afrikaans background - Learn is very similar to the Afrikaans word Leer and so I make the connection.
___ English look to people what learns it
Filling in the first word? we've come pretty far!
The first word, from basic grammar, can only be something that asks something or describes something and can easily follow how we incorporated "learn"
"What English look to people what learns it"
I would say this is about 50% correct grammatically and is perfectly understandable and would be seen as a great first step to anyone trying to learn the English Language.
Obviously written correctly as "How English looks to people learning it"
side note, Where I am isn't very English, but the local university is so everyone has to know or learn it.
I know lots of people who actually talk like this