Start a new language pair involving Interlingua using the Apertium new language HOWTO. Interlingua is the second most used "artificial" language, after Esperanto). As Interlingua is basically a Romance language, you can use a Romance language as the other language, and Romance-language dictionaries rules may be easily adapted. Include at least 50 very frequent words (including some grammatical words) and at least one noun--phrase transfer rule in the ia→X direction.