Re: Actually "Tigrigna" is correct.... Atsbe-Derans, the most ancient Tigreans, do call themselves "we are Tigrigna".
After all, we all correctly say : he/she is English, and he/she speaks English; He/she is German, and speaks German: he/she is Italian, and speaks Italian, etc; so there is reason why one cannot be Tigrigna and speak Tigrigna.