language is indeed important. Nevertheless, if say a person of complete Anglo-Celtic ancestry learnt Armenian - I would not consider him an Armenian, if he/she also practiced/embraced the culture AND considered themselves Armenian, I would recognise them as such regardless of having Armenian parents/grandparents etc.
on the other hand:
I disagree, I would not consider someone with 'full Armenian blood', but without any knowledge of the language or culture and without showing any interest in it, an Armenian (even if they had a mono-brow and curly hair on back ).