Q1. 'How do you get the Mexicans to do it?' A1: Here, "get" means tell/ask/give a job or task to. In other words, to induce someone to do something. Q2. 'I'll get John to get you the water' A2: The first get in this sentence is the same as Q1. The second "get" in this sentence means "to attain". Q3. 'Do both sentences sound natural?' A3.1 Both sound grammatical. A3.2 The first sentence sounds very general, especially with no context. A3.3 The second sentence sounds a little repetitive or redundant because "get" has been used twice. I hope this helped! -Dustin :)

From my point of view, both sentences sound quite natural. The expression "to get smb to do smth' is the colloquial synonim of another one, which is familiar to you, I think: "to make smb do smth". As for me, I'd avoid repetition in the second example - 'I'll GETJohn to GET you the water'. "I'd rather replace the second "get" by... "bring", for instance. Hope my advice was useful!

To "get" something is a way of doing something or having someone else do something. Both of the sentences sound natural. "How do you get the Mexicans to do it?" It is basically saying "What do we have to do so the Mexicans will do it?" "I'll get John to get you the water" Meaning the person talking will make sure John hands you water. John will "get" the water for you, instead of you having to "get it" (pick up the water) yourself. Get can also mean understanding something. If someone tried to explain something to you and said "so do you get it?" It's the same as saying "so do you understand?" The correct response will be "Yes, I get it" (Meaning I understand) or "No, I don't get it (Don't understand), can you explain more?