Simple PHP string search and replace translator

Synopsis: A home project to provide an online simple translation service. User will be presented with a simple form with two textarea input fields. They enter plain English into the first textarea, click submit and then given the translation displayed in the second textarea. The site will be hosted on a PHP apache server with a MySQL database. Description A backend MySQL database to contain a list of matching keypairs of English and Foreign words and phrases. There will be 1000’s of rows. Each DB record can contain single word pairs or multi-word phrases (up to 4 word phrases). The idea is for the English string to be broken down and searched within the database. Matching words and phrases are then transposed to form a new string consisting of the Foreign text. The search and replace must cater for single word match, up to four word phrase matches, special characters, punctuation and case. Example: He said, “That’s a REALLY nice black cat!”. It was a very good day. Example extract from DB table: that’s | that is really nice | very cool black | noir cat | dog very good | v-good it was | t’was The | pipe is the delimiter. The translation would therefore read: He said, “That is a VERY cool noir dog!”. T’was a v-good day. I am open to be flexible on the translation process if there is a simpler way. The DB can also be structured and orders as required.