C++11 Threads How to split task

I'm writing a program which reads content of file,then split all words as a separatly and count them. In some moment i have to create a vector of unique words, to check the list of words already counted to avoid counting this same words over and over again. This cost a lot of power. So i figure out that I will split this task on dynamicly created theards.Theards numbers will be incresed proportionally to numbers of words stored in vector. How should i do that ? I was redesigned whole program couple of times. I was trying to create thread as function, as separeted class. IMPORTANT The problem is that I have to pass as a parrametr to theard function id which will be a number just created thread to be able correcty divide range of vector to search. Thanks for help.

void Text::coutingWords()
{

int num;               
vector<string>buffor;
bool  flaga=true;
for( int i=0; i<_tekst.size(); i++) // MAIN LOOP through vector of separated words stored whole content
{
    num=0;    // counter of words;
    string temp =_tekst[i]; 
    int threadNumbers=0;  
    if(!(threadNumbers=(int)buffor.size()/100)) //evry 100 counted words is creating new thread
        threadNumbers=1; //if 0 will be 1;

    thread t1[threadNumbers];  //array of threads

    for(int h=0; h<threadNumbers; h++)
    {
        thread(wordsCounting,buffor,h,threadNumbers,temp,flaga); //running threads and passing parrametrs
    }
    for(int h=0; h<threadNumbers; h++)
    {
        t1[h].join();
    }
    if(flaga) //bool variable decide if current words should be counted through whole content
    {
        for(int j=0; j<_tekst.size(); j++)  //couting
        {
            if(_tekst[i].compare(_tekst[j])==0)
            {
                ++num; 
            }
        }
        buffor.push_back(_tekst[i]);  //local vector of unique words <- Thread should work on it
        _counted[_tekst[i]]=num; // map as a key is unique words and value is just how many time apper in content
    }
}

}

This should be thread function;

void Text::wordsCounting(vector<string>& buffor,const int id,const int threadNumber,string tekst,bool& flaga)
{ 

    //Example...counted 253 words so 2 threads created.(every 100 1 thread)
    //thread number 2. id=2;
    //Step 126,topRange=253;bottomRange = 127;
int Step =buffor.size()/threadNumber; 
int topRange=(buffor.size()/threadNumber)*id;  
int bottomRange= topRange-Step;
for(int bottomRange; bottomRange<topRange; bottomRange++)
{
    for(int m=0; m<tekst.size(); m++)
    {
        if(tekst.compare(buffor[bottomRange])==0)   //checking 
            flaga=false; //if found change flag this will avoid couting content using this word.
    }
}

}

This is my error error: no type named 'type' in 'class std::result_of >&, int, int, std::basic_string, bool&)>(std::vector >, int, int, std::basic_string, bool)>'|