Please add the language code fro (Old French Q35222) and frm (Middle French Q1473289 ) to the list of language codes supported for monolingual text values.
It's needed for bibliographical data. For example: in Q19211174 for P1476 = "Les grans et merueilleux faictz du ſeigneur Nemo" (I temporary used the ISO 639 code "mis" with a qualifier)