A dictionary for text messaging. Well, that's something new. How many entries does it have? Is it light and humorous? Who is the intended audience? Have you written a proposal yet? If not, you need to before you can consider contacting any publishers.
For something like this, it'd be best to try agents first that are looking for nonfiction. Research each agent to see if they're looking specifically for pop culture material.
I'd suggest you post your query in AW's Query Letter Hell in the Share Your Work forum, but you only have four posts, and you need at least fifty.
Spend some time around AW and get to know publishing and the community.
And welcome to AW.