What you're making there is a cryptogram which is a puzzle used alongside newspaper crosswords.
For either of those nonsense strings, a simple online cryptogram solver (http://rumkin.com/tools/cipher/cryptogram-solver.php) will generate the two words you chose along with the hundreds of other words that fit. With a larger sample, it would start to find words there which didn't allow for other words in the string to be created, rule those keys out and continue until it had the only viable key. Unless you have a way to preserve your intended word choice, your method would mask the intended message from your recipient, defeating the purpose.
For either of those nonsense strings, a simple online cryptogram solver (http://rumkin.com/tools/cipher/cryptogram-solver.php) will generate the two words you chose along with the hundreds of other words that fit. With a larger sample, it would start to find words there which didn't allow for other words in the string to be created, rule those keys out and continue until it had the only viable key. Unless you have a way to preserve your intended word choice, your method would mask the intended message from your recipient, defeating the purpose.