In English you need to be very careful with commas. Yes, it can change the whole meaning. There's a book titled 'Eats, shoots and leaves' that discusses this well. Eats, shoots and leaves (verb) is very different from Eats shoots and leaves (noun). The 'horse' sentences you have written don't seem to have any differences, except for the pause you give to your speaking where the comma is. The 'Ray' sentences lack clarity anyway. Meaning 1: Ray, you are very responsible (even for a child of mine - my children are all responsible and you particularly so) so please take care of this other person (the 'him' of the sentence). = Ray is the speaker's child Meaning 2: Ray, you are very responsible (even for a child of mine - I even consider you responsible enough to look after MY child!) so please take care of him (the speaker's child). = Ray is not the speaker's child. Does anybody else feel there is ambiguity here? Who is 'him'? I think I prefer a different word order to remove any confusion, and only then should we look at the commas.

Those commas aren't changing the meaning but the pace of the sentences. I'd say that English is not as susceptible to this matter as Spanish.