The grammar and sentence structure is SVO, same as English. There's no gender, cases, plurals, etc. Mandarin phonemes are also limited, there's fewer sounds than English.
The real barrier is mental. Mandarin can be picked up by barbarian warlords.
I'll say english is a bit more forgiving than Mandarin is, once you know all 26 characters in english, spelling can simply be generlised via pronuuociation barring a few weird cases, if you know the length of the word and begining and end of each word, you can work out it's meaning even if it is missqelt, you can see a few deliberately misspellings in what I've typed and it's still perfectly legible.
Chinese writing on the other hand is heavily dependent on memorising characters, with something like 3000 seperate characters for basic every day use. Granted Chinese characters are also similar to english in that each character is based on a combination of smaller base set of characters, but it is not as easily combined as English is.
Nothing insurmountable, of course. Seeing how easily Chinese people learn english it's not like the inverse can't be true. Just need to start young.