You'll need to parse the data through some sort of text processing software first to 'tokenise' the data and get a count of each word. Tableau can't do this on it's own.
I've done this before with free software such as Rapid Miner
Wordclouds are not available on the show me, but you can choose bubble, then change the mark type to text. You will likely have to filter words like "the, and, phone" etc. out