Simplify the following text for a Grade 16 native English-speaking person.
Original: In the foreword , young StarÄ eviÄ elaborated his linguistic ideas , pointing out that the mixture of all three Croatian dialects ( Shtokavian , Chakavian ) and Kajkavian ) and the Krajina dialect is called the Croatian language , which StarÄ eviÄ considers from the perspective of its six hundred years of history .
Simplified: In the foreword , young StarÄ eviÄ elaborated his linguistic ideas , specifically that the mixture of all three Croatian dialects ( Shtokavian , Chakavian and Kajkavian ) and the Krajina dialect , with its 600 year history , was the Croatian language .