*scratches head*

the "so" one is easy...   its usually used when describing how an event or scenario being discussed came to be...   the ending of the sentence with so....   is because you have come full circle in the conversation & (usually) the other person is following where the discussion is going so the rest of the sentence is not required.

When the other person isn't following where the discussion is going, or in cases where the think they might be, but want the other person to spell it out (usually in hostile conversations) their reply will be  "...so.... what?  what is it you are trying to say?"

I've never really understood why people put 'and he/she turned round' before relaying what they said. Weird!

All that turning around must make folk dizzy

Brisket, I feel like you do about the abuse of the English (or any other) language, especially as I had to go through 8 years of learning it properly, but I also believe that language evolves and it's not always universally liked. I remember my mother making comments about the way we talked in the 60s.

I'm sure you are right about evolving language cologne 
The trouble is that I resent so many of the changes rather than simply accepting them.
I'm just an old reacontionary at heart.
I do particularly bemoan the lack of the letter T.
The glottal stop and no T sound is not just saaarff london any more - it's all over the country.
I find the lost Ts particularly sad.

When did " yeahyeahyeah" happen?

Erm, erm, erm....Wayne Rooney says 'erm' after EVERY other word

I don't know  Slinki    but John James has extended to half-a-dozen "yeahs".
Likewise with "Na, na, na, na, na, na, nah."

That made me think of the Banana Splits

I'm quite laid back about language evolution...  though constant repetition gets on my nerves... e.g. "like" at the end of every sentence.

But 'dropped t's' as my Mum called them were a total no no in my house when I was growing up... and as a result I don't tolerate it from my kids either.

my real name is Katie...  and I will never forget the toe curling shame when my mother pulled one of my school friends up on calling me "Ka'ie"...    t'was sooooo embarrassing!

That phrase or it's equivalent has been around for a very long time. There are uses of this in the Bible. For instance from John 20:16 in the King James version there is:
"Jesus saith unto her, Mary. She turned herself, and saith unto him, Rabboni; which is to say, Master."

Probably 1963 when the Beatles released "She Loves You".

From Wikipedia:

The British music establishment at that time found the phrase "yeah" controversial. National radio in the form of the BBC broadcast the single and "in some quarters it was seen to hail the collapse of civilised society". Lennon, being mindful of Elvis Presley's "All Shook Up", wanted something equally as stirring: "I don't know where the 'yeah yeah yeah' came from. I remember when Elvis did "All Shook Up" it was the first time in my life that I had heard 'uh huh', 'oh yeah', and 'yeah yeah' all sung in the same song". "The 'wooooo' was taken from The Isley Brothers' 'Twist And Shout'. We stuck it in everything". McCartney recalls them playing the finished song on acoustic guitars to his father at home immediately after the song was completed: "We went into the living room [and said] 'Dad, listen to this. What do you think? And he said 'That's very nice son, but there's enough of these Americanisms around. Couldn't you sing "She loves you, yes, yes, yes!". At which point we collapsed in a heap and said 'No, Dad, you don't quite get it!'".

George Martin, the Beatles' producer, questioned the validity of the major sixth chord that ends the song, an idea suggested by George Harrison "They sort of finished on this curious singing chord which was a major sixth, with George [Harrison] doing the sixth and the others doing the third and fifth in the chord. It was just like a Glen Miller arrangement". McCartney later reflected: "We took it to George Martin and sang 'She loves you, yeah, yeah, yeah, yeeeeeaah…' and that tight little sixth cluster we had at the end. George said: 'It's very corny, I would never end on a sixth'. But we said 'It's such a great sound, it doesn't matter'"

Ditty.....I'm liking you more and more.      This must stop.

Thanks El Loro  for furthering my education.   
I had no idea that  someone turned and saith in the bible!!
And the extract about the Beatles is interesting.
GaGaJoyJoy is becoming a mine of information

Oh flip! Seeing your name Brisket has just reminded me that I forgot to buy some pastrami from the deli counter when I went to Selfridges yesterday. Damn! 

You forgot to add Like to that Brisket. " So he turned round like and said like....yea yea yea yea" and my favourite one when answering a question in the positive "no, yes" or like wise "yes, no".  
Throw back to The Vicar of Dibley maybe but I've heard respected tv presenters doing it. 

(should that have been likewise or alternatively)  Where exactly should the question mark go?  Inside or outside the brackets?  It's too much.  

suzybean    I'm pleased to learn that I have my uses. 

and
Tayto  - yes that "Yes, no" or "No, yes" business always tickles me. It usually seems to be said without thought.
As for "like"     - oh don't get me going. It drives me daft, (or should that be dafter.) 

I have very definite views on this subject.  I spent my formative years surrounded by a bunch of conservative countryfolk and vowed that I would never turn grumpy like them. English is a wonderful language which lends itself to a bit of misuse, creativity, or bricolage, here and there. In some ways it's refreshing that we can view people using and abusing it. In my day if you didn't use the Queen's English you had no chance of fame or fortune but.