Instead of reading a blog post, why don't you listen to this program from the BBC Radio 4 (Word of Mouth). This is a fascinating half hour programme on languages that raises so many interesting questions concerning the concept of a mother tongue, loss and shift.
I found the beginning quite emotional and sad. I completely agreed with Jan's shift of personality (depending on what language you speak) too. I thoroughly recommend a listen. Not sure how long it is going to be available for, so listen to it now!
I loved Dean Atta's poem:
I can’t tell you why she would wilfully deny
Her daughter and her son
But she has swallowed it
And we are struck dumb
Our mother has swallowed her tongue.