Standard Chinese can be spoken in Cantonese, but while understandable, it is never done, in contrast to Mandarin.
In recent years written online conversations (like blogs, Facebook posts, instant messages) by Cantonese speakers are increasingly written in Cantonese instead, and this is slowly spreading to more "formal" media such as books.
Source: I'm a native Cantonese speaker.
They're still a lot closer than English and Spanish or even French and Spanish (https://www.ezglot.com/most-similar-languages.php).
E.g. I bought this book: ngóh(S) maáihjó(V) nìbún syù(O).
Contrast with Japanese: watashi wa(S) kono hon o(O) kaimashita(V).
Differences from Mandarin Grammar are listed here: https://en.wikipedia.org/wiki/Cantonese_grammar#Differences_...
Classical Chinese is also SVO: https://en.wikipedia.org/wiki/Classical_Chinese_grammar