Here's a bit of my experience to back up how hard it is to separate out the cultural aspect: The English singular 'you' has two words for it in German, 'sie' and 'du'.

The first one is used in situations where there is some distance between the speakers, the second when they are (much) more familiar. It used to be fairly unheard of to hear a German 'subordinate' use 'du' to their superior, whereas in English it would be impossible to even express the difference.

So in Germany workplace relationships tend to have a sense of distance between the various strata. Even if you didn't want to change your personality the simple fact that you'd address your superior in this way would make you behave differently (and so you would show a more deferential personality), because associated with that distance are a whole pile of other personal traits.

It's not as strict as it used to be, but the difference is definitely still there.

Korean and Japanese have several levels of deference, which go beyond a simple dual 2nd person pronoun. There are, for example, different 1st person pronouns which are used for self-reference when the listener is of various social ranks, or under different social circumstances.

In Japanese, for example, a man will say "watashi" for "I" under formal circumstances, and "ore" while getting a beer with the mates.

Same in Spanish ('usted' and 'tu', respectively).

And in most Indian languages.

And French, "tu" (familiar singular) and "vous" (formal singular, or plural).

English used to have "thou", but of course that's long since extinct.

Trivia, "thou" was actually the informal pronoun.

On the other hand in Mexican Spanish, "usted" is fading away. It's curious how different cultures get rid of different options.

"Usted" is alive and well in Argentinian Spanish. Divided by a common language indeed...

In Italian is almost like that: "tu" (familiar) and "voi" (very formal) or "lei" (less formal)

And Russian.

And Czech. And Dutch

And Afrikaans: jy (familiar), u (ever so formal), but u is (or seems to be) falling out of common use.

And in Turkish. "Sen" ve "Siz".

And Spanish, "Tu" vs "Usted" vs "Vos"

Hindi has three - tu, tum and aap. I explained some of this on my Hindi lessons site - http://hindipedia.com/hindi-video-lesson-04-pronouns.

The problem with the German version is that "Sie" also means "she" and "they". Usted at least does not mean "she."

So, are you talking about your sister… or are you talking to your superior? (My 2nd most hated thing about German.)

Italian also has "Lei" which means both she and you (in the formal sense).

But English has rules too. Not as clear cut as German, but you wouldn't say 'sup mate?' to you boss, you use a different vocabulary when talking to a superior.

As it used to be in English: "thou" and "you".

I'd definitely fall into the coordinate bilingual w/ personality shift camp. I think, speak and act in one language or the other, and have difficultly translating, though my comprehension is fluent, like two hemispheres of the brain with impaired communication.

I think two other variables needs to be factored in: cultural influence of the native speakers of the languages and the age at which you acquire the. I can attest to the second factor because I learned four languages before I was six (typical if you grow up in India) and still use three of them almost every day and I do not feel any discernible personality change when I shift the language I speak or think in.

I would be very interested in this thesis, is there any way I could get an advance copy? it relates to my start-up, 321speak.com

No, sorry. As I say, it's unfinished, it's not mine, and I specifically don't have permission to disseminate it. I can talk about what I know from it, but I can't quote from it. You might email me with any specific questions and I'll answer them if I can.

Why do you need permission to post your own writing? Do you sign some kind of NDA when you enter a phd program?

It's not mine, and it's a long story. The short version is that a chap I know - nowin his 70s - never finished his PhD. We were chatting about the SWH and linguistic relativism and he mentioned it. I asked to see it, he loaned it to me - with permission to copy - provided I never made any of it public.

I'm slowly trying to persuade him that it wouldn't be a bad thing, but it's slow work. He also has the early symptoms of Alzheimer's, so it may never happen.

Does this relate at all to linguistic relativity?