The only thing which can determine the price of bitcoin is the dollar value.
No. You can use the fiat of your country to determine the price of bitcoin, not necessarily USD.
I live in Pakistan and we have the currency PKR. Our currency is very much devalued against dollar in last two month but the bitcoin prices are not increasing with this ratio. This means that only the global currency like US dollar only has an effect on the bitcoin prices.
You can share your currency and we can further compare it to see if this holds true for other currencies also.