Improving database design, is this a valid case for entity attribute values?
I think that your proposed approach with a table row per language is fine, but I would definitely have language be a foreign key to a lookup table of languages.
Otherwise you'll end up with languages like English, en, EN or sprfz that people enter on a whim, and you will get complaints why the program does not display the proper English version of the text. Prefill that lookup table with entries for all conceivable languages.