If comprehension skills are low, it follows (especially in English) that spelling of words that sound the same (which the context within which they are used is not understood) will be spelt wrongly.
The ability to read is far more than reiterating words.
Reading widely for the love of reading in one's language, especially "world" languages like English, Spanish, French and Portuguese will contextualise one's comprehension and usage of said languages in a richer and far more complex way.
To read and understand different dialects, yet be able to easily switch and use "standard"/"received" English from one's English speaking country is a skill and a joy that keeps the brain supple.
Thus making it more receptive to recognising, and differentiating foreign languaged by sight, even if one may not understand the words.
This even goes for languages with a whole different calligraphy than what is used in Europe (including Russian and Greek).
This has worked for me with just an O'level standard of education, but coming from homes that always had books "high and low" in them and a father that bought the Daily Mirror Monday- Saturday and the Sunday Mirror and the Observer on a Sunday.
Between the two of them, my parents sent me to school knowing how to read and write.
Neither left school with qualifications, but were very intelligent due to their curiosity, code switching skills and love of reading and being able to communicate with ANYBODY.