An innocent British girl went into a loncheria looking for elevenses and confidently asked 
for (what she thought was) a cup of hot cocoa. As a grin spread across the proprietor’s broad face she realised her mistake.
Instead of asking for that which she required – ‘chocolate caliente’ – she had requested a class A drug – ‘coca’. Fortunately the kind owner did not call the Feds and she left feeling mildly humiliated, ready to continue her battle to master basic conversational Spanish. More linguistic blunders shall occur, of that I am sure.