Woody Allen's Vicky Cristina Barcelona

In Woody Allen's film Vicky Cristina Barcelona (2008), there is a scene where the main male character Juan Antonio explains why his father, a poet, refuses to learn another language aside from his mother tongue: "He's a poet and he writes the most beautiful sentences in the Spanish language and he doesn't believe that a poet should pollute his works by any other tongue." Allen is known to use his characters either as spokespersons or foils; either way, the idea of sticking to only one language to keep one's literary art pure is worth exploring. Using whatever literary standards we believe in, can we say that a monolingual poet is more "pure" than a poet that writes in a second language?